CDX digital currency trading platform

1. Functions for VFP:
1 Visual FoxPro database function
adatabases() puts the names and paths of all open databases into a memory variable array
adobjects() puts the named connection name, relationship name, table name or SQL view name in the current database into a memory variable array
afields() stores the structure information of the current table in an array, And returns the number of fields in the table
alias() returns the alias of the current table or the specified workspace
assignments() creates an existing data work period ID array
ataginfo() creates a name containing index and key expression Array of quantity and type information
aused() stores the table alias and workspace in a data working period into the memory variable array
bof() determines whether the current record pointer is in the header
candidate() determines whether the index is a candidate index
cdx() numbers according to the specified index position, Returns the name of the open composite index (. CDX) file
cpdbp() returns the code page used by an open table
create offline() creates a free view from an existing view
cursorgetprop() returns the current property settings of the VisualFoxpro table or temporary table
cursorsetprop() specifies the property settings of the VisualFoxpro table or temporary table
cursortoxml() converts visualf Oxpro temporary table is XML text
curval() returns field values directly from a table on disk or a remote data source
dbc() returns the name and path of the current database
dbf() returns the name of the table opened in the specified workspace, or returns the name of the table according to the table alias
dbsetprop() gives the current database or the fields, named connections The table or view sets an attribute
deleted() to return a logical value indicating whether the current record is marked with a deletion mark
deleting() creates an index ID with the deleting keyword
dropoffline() discards all modifications to the free view, And put the free view back to the database
eof() determines whether the record pointer position exceeds the current table or the last record in the specified table
fcount() returns the number of fields in the table
field() returns the field name in the table according to the number
filter() returns the table filter expression specified in setfilter command
fldlist() for the field list specified by setfields command, Return the field and calculation result field expression
block() attempts to lock the current table or the specified table
for() returns an open single index file or index filter expression of index ID
find() if continue, find, locate or seek command is executed successfully, the return value of the function is & quot; True & quot<
fsize() returns the size of the specified field or file in bytes
getfldstate() returns a value indicating whether the field in the table or temporary table has been edited, whether there are additional records, or whether the deletion status of the record has changed
getextmodified() returns a record number, Corresponding to the next modified record in the buffer table or temporary table,
header() returns the number of bytes occupied by the header of the current or specified table file
idxcollate() returns the sort sequence of index or index ID
indbc() returns & quot; if the specified database object is in the current database; True & quot; ( T. )
indexseek() searches an index table for a record that appears for the first time
isexclusive() judges whether a table or database is opened in exclusive mode
islocked() returns the lock state of the table
isreadonly() judges whether to open the table in read-only mode
isrlocked() returns the lock state of the record
key() returns the index of the index ID or index file Keyword expression
keymatch() searches for an index keyword in the index ID or index file
lookup() searches for the first record whose field value matches the specified expression in the table
update() returns the date of the last update of a table
mdx() returns the open. CDX composite index file name according to the specified index number
memlines() returns remarks Section
mline() returns the specified line in the remarks field in the form of string
ndx() returns the name of an index (jdx) file opened for the current table or the specified table
order() returns the master index file or identifier of the current table or the specified table
primary() checks the index identifier, if it is the master index identifier, it returns & quot; True & quot; ( T. )
reccount() returns the number of records in the current or specified table
recno() returns the current record number in the current or specified table
recsize() returns the size (width) of the records in the table
refresh() refreshes the data in the updatable SQL view
relaxation() returns the relationship expression specified for the table opened in the given workspace
seek() in an established query Search for the first occurrence position of a record in the referenced table
select() returns the current workspace number or the maximum number of unused workspaces
setfldstate() specifies the field status value or deletion status value for the field or record in the table or temporary table
sqlcall() requests to cancel an executing SQL statement
sqlcalls() to specify the column name and about of the data source table The information of each column is stored in a VisualFoxpro temporary table
sqlconnect() submits a transaction
sqlconnect() establishes a connection to the data source
sqlconnect() terminates the connection with the data source
sqlexec() sends an SQL statement to the data source for processing
sqlgetprop() returns the current or default setting of an active connection
sqlmoreresults() If there are multiple result sets, another result set to the temporary table of VisualFoxpro
sqlprepare() before using sqlexec() to perform remote data operation, You can use this function to prepare the remote data for the command to be executed
sqlcallback() to cancel any changes made ring the current transaction
sqlsetup() to specify the setting of an active connection
sqlstringconnect() to use a connection string to establish a connection with the data source
sqltables() to store the table name in the data source in the temporary table of VisualFoxpro
sqltables() />Sys (14) index expression
sys (21) control index number
sys (22) control identifier name or index name
sys (2011) returns the status of record locking or table locking in the current workspace
sys (2012) returns the remark field block size of the table
sys (2021) screens the index expression
sys (2029) returns the value corresponding to the table type
sys (3054) Rushmore optimization level & 822 6;
tag() returns the identification name of the opened. CDX multiple index file, Or return the file name of the opened. IDX single index file
tagcount() returns the composite index file (. CDX) ID and the number of opened single index files (. IDX)
tagno() returns the composite index file (. CDX) ID and the index location of the opened single index file (. IDX)
target() returns the alias of a table, This table is the target of the relationship specified in the into clause of the setreading command.
unique() is used to test whether the index is created in a unique way.
updated() is used to test whether the index is created in the latest read command, Whether the data has been modified
used() determines whether a table is opened in the specified workspace
xmlcursor() converts XML text to a Visual FoxPro cursor or table

2 Visual FoxPro date and time functions
ctod() converts character expressions to date expressions
cdow() returns the value of the week from a given date or date time expression
cmonth() returns the month name of a given date or date time expression
ctod() converts character expressions to date expressions
ctot() returns a date time value from a character expression
date() returns the current system date of the operating system control, or creates a date value compatible with the year 2000
datetime() returns the current date and time with a date time value, or creates a 2000 compatible date time value
day() returns the number of days in a given day expression or date time expression
dmy() returns a character expression in the format of "day month year" from a date or date time expression (for example, 31 May 1995). The name of the month is not abbreviated
dtoc() returns a character date from a date or date time expression
dtos() returns a string date in yyyymmdd format from a specified date or date time expression
dtot() returns a date time type value from a date type expression
for a given date expression or date time expression, gomonth() returns the date before or after the specified number of months
hour() returns the hour part of a date time expression
mdy() returns the specified date or date time expression in month day year format, where the month name is not abbreviated
minute() returns the minute part of a datetime expression
month() returns the month value of a given date or date time expression
quarter() returns the quarter value in a date or date time expression
sec() returns the second part of the datetime expression
seconds() returns the time since midnight in seconds
sys (1) returns the current system date in the form of date numeric string
sys (2) returns the time since midnight, in seconds
sys (10) converts the (Julian) date to a string
sys (11) converts the date expression or string represented by date format to (Julian) date
time() returns the current system time in 24-hour format and 8-bit string (hour: minute: Second) format
ttoc() returns a character value from a date time expression
ttod() returns a date value from a date time expression
week() returns a number representing the week of the year from a date or date time expression
year() returns the year from the specified date expression<

3 Visual FoxPro character function
alltrim(). Delete the space character before and after the specified character expression
asc() returns the ANSI value of the leftmost character in the character expression
at() returns the first occurrence position of one character expression or remark field in another character expression or remark field
at()_ C() returns the position where a character expression or remark field first appears in another character expression or remark field
atc() returns the position where a character expression or remark field first appears in another character expression or remark field
atcc() returns the position where a character expression or remark field first appears in another character expression or remark field Current location
addbs () if necessary, Add a backslash to a path expression
atcline() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
at line() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
between() determines the value of an expression No, between the values of two other expressions of the same data type,
chr() returns its corresponding characters according to the specified ANSI numeric code,
chrtran() replaces the characters in the first character expression that match those in the second expression with those in the third expression

2. Visual FoxPro database function

adatabases() puts the names and paths of all open databases into a memory variable array
objects() puts the named connection name, relationship name, table name or SQL view name in the current database into a memory variable array
afields() stores the structure information of the current table in an array, And returns the number of fields in the table
alias() returns the alias of the current table or the specified workspace
assignments() creates an existing data work period ID array
ataginfo() creates a name containing index and key expression Array of quantity and type information
aused() stores the table alias and workspace in a data working period into the memory variable array
bof() determines whether the current record pointer is in the header
candidate() determines whether the index is a candidate index
cdx() numbers according to the specified index position, Returns the name of the opened composite index (. CDX) file
cpdbp() returns the code page used by an open table
create offline() creates a free view from an existing view
cursorgetprop() returns the current property settings of the VisualFoxpro table or temporary table
cursorsetprop() specifies the property settings of the VisualFoxpro table or temporary table
cursortoxml() conversion VI Sualfoxpro temporary table is XML text,
curval() returns field values directly from a table on disk or a remote data source,
dbc() returns the name and path of the current database,
dbf() returns the name of the table opened in the specified workspace, or returns the name of the table according to the table alias,
dbsetprop() gives the current database or the fields and connections in the current database The table or view sets an attribute
deleted() to return a logical value indicating whether the current record is marked with a deletion mark
deleting() creates an index ID with the deleting keyword
dropoffline() discards all modifications to the free view, And put the free view back to the database
eof() determines whether the record pointer position exceeds the current table or the last record in the specified table
fcount() returns the number of fields in the table
field() returns the field name in the table according to the number
filter() returns the table filter expression specified in setfilter command
fldlist() returns the field column specified by setfields command Table, return the field and calculation result field expression
block() attempts to lock the current table or the specified table
for() returns the index filter expression of an opened single index file or index ID
find() if the continue, find, locate or seek command is executed successfully, the return value of the function is & quot; True & quot<
fsize() returns the size of the specified field or file in bytes
getfldstate() returns a value indicating whether the field in the table or temporary table has been edited, whether there are additional records, or whether the deletion status of the record has changed
getextmodified() returns a record number, Corresponding to the next modified record in the buffer table or temporary table,
header() returns the number of bytes occupied by the header of the current or specified table file
idxcollate() returns the sort sequence of index or index ID
indbc() returns & quot; if the specified database object is in the current database; True & quot; ( T. )
indexseek() searches an index table for a record that appears for the first time
isexclusive() judges whether a table or database is opened in exclusive mode
islocked() returns the lock status of the table
isreadonly() judges whether to open the table in read-only mode
isrlocked() returns the lock status of the record
key() returns the lock status of the index ID or index file Index keyword expression
keymatch() searches for an index keyword in the index ID or index file
lookup() searches for the first record in the table whose field value matches the specified expression
update() returns the latest update date of a table
mdx() returns the open. CDX composite index file name according to the specified index number
memlines() returns The number of rows in the comment field
mline() returns the specified row in the comment field in the form of string
ndx() returns the name of a jdx file opened for the current table or the specified table
order() returns the master index file or identifier of the current table or the specified table
primary() checks the index identifier, and if it is the master index identifier, returns & quot; True & quot; ( T. )
reccount() returns the number of records in the current or specified table
recno() returns the current record number in the current or specified table
recsize() returns the size (width) of the records in the table
refresh() refreshes the data in the updatable SQL view
relaxation() returns the relationship expression specified for the table opened in the given workspace
seek() in a built Search the first occurrence position of a record in the indexed table
select() returns the current workspace number or the maximum number of unused workspace
setfldstate() specifies the field status value or deletion status value for the field or record in the table or temporary table
sqlcell() requests to cancel an executing SQL statement
sqllinks() to specify the column name of the data source table And the information about each column is stored in a temporary table of Visual FoxPro
sqlconnect() submits a transaction
sqlconnect() establishes a connection to the data source
sqlconnect() terminates the connection to the data source
sqlexec() sends an SQL statement to the data source for processing
sqlgetprop() returns the current or default setting of an active connection
sql Moreresults() if there are multiple result sets, another result set to the temporary table of VisualFoxpro
sqlcompare() before using sqlexec() to perform remote data operation, You can use this function to prepare the remote data for the command to be executed
sqlcallback() to cancel any changes made ring the current transaction
sqlsetup() to specify the setting of an active connection
sqlstringconnect() to use a connection string to establish a connection with the data source
sqltables() to store the table name in the data source to the temporary table of VisualFoxpro In
sys (14) index expression
sys (21) control index number
sys (22) control identifier name or index name
sys (2011) returns the status of record locking or table locking in the current workspace
sys (2012) returns the remark field block size of the table
sys (2021) filter index expression
sys (2029) returns the value corresponding to the table type
sys (3054) Rushmore optimization Level ·
tag() returns the identification name of the opened. CDX multiple index file, Or return the file name of the opened. IDX single index file
tagcount() returns the composite index file (. CDX) ID and the number of opened single index files (. IDX)
tagno() returns the composite index file (. CDX) ID and the index location of the opened single index file (. IDX)
target() returns the alias of a table, This table is the target of the relationship specified in the into clause of the setreading command.
unique() is used to test whether the index is created in a unique way.
updated() is used to test whether the index is created in the latest read command, Whether the data has been modified
used() determines whether a table has been opened in the specified workspace
xmlcursor() converts XML text to a VisualFoxpro cursor or table

: --- -

Visual FoxPro date and time functions
ctod() converts character expressions to date expressions
cdow() returns the value of the week from a given date or date time expression
cmonth() returns the month name of a given date or date time expression
ctod() converts character expressions to date expressions
ctot() returns a date time value from a character expression
date() returns the current system date of the operating system control, or creates a date value compatible with the year 2000
datetime() returns the current date and time with a date time value, or creates a 2000 compatible date time value
day() returns the number of days in a given day expression or date time expression
dmy() returns a character expression in the format of "day month year" from a date or date time expression (for example, 31 May 1995). The name of the month is not abbreviated
dtoc() returns a character date from a date or date time expression
dtos() returns a string date in yyyymmdd format from a specified date or date time expression
dtot() returns a date time type value from a date type expression
for a given date expression or date time expression, gomonth() returns the date before or after the specified number of months
hour() returns the hour part of a date time expression
mdy() returns the specified date or date time expression in month day year format, where the month name is not abbreviated
minute() returns the minute part of a datetime expression
month() returns the month value of a given date or date time expression
quarter() returns the quarter value in a date or date time expression
sec() returns the second part of the datetime expression
seconds() returns the time since midnight in seconds
sys (1) returns the current system date in the form of date numeric string
sys (2) returns the time since midnight, in seconds
sys (10) converts the (Julian) date to a string
sys (11) converts the date expression or string represented by date format to (Julian) date
time() returns the current system time in 24-hour format and 8-bit string (hour: minute: Second) format
ttoc() returns a character value from a date time expression
ttod() returns a date value from a date time expression
week() returns a number representing the week of the year from a date or date time expression
year() returns the year from the specified date expression

Visual FoxPro character function

alltrim(). Delete the space character before and after the specified character expression
asc() returns the ANSI value of the leftmost character in the character expression
at() returns the first occurrence position of one character expression or remark field in another character expression or remark field
at()_ C() returns the position where a character expression or remark field first appears in another character expression or remark field
atc() returns the position where a character expression or remark field first appears in another character expression or remark field
atcc() returns the position where a character expression or remark field first appears in another character expression or remark field Location
addbs () if necessary, Add a backslash to a path expression
atcline() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
at line() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
between() determines whether the value of an expression is correct Between the values of two other expressions of the same data type,
chr() returns its value according to the specified ANSI numeric code

3. Visual FoxPro database function

adatabases() puts the names and paths of all open databases into a memory variable array
objects() puts the named connection name, relationship name, table name or SQL view name in the current database into a memory variable array
afields() stores the structure information of the current table in an array, And returns the number of fields in the table
alias() returns the alias of the current table or the specified workspace
assignments() creates an existing data work period ID array
ataginfo() creates a name containing index and key expression Array of quantity and type information
aused() stores the table alias and workspace in a data working period into the memory variable array
bof() determines whether the current record pointer is in the header
candidate() determines whether the index is a candidate index
cdx() numbers according to the specified index position, Returns the name of the opened composite index (. CDX) file
cpdbp() returns the code page used by an open table
create offline() creates a free view from an existing view
cursorgetprop() returns the current property settings of the VisualFoxpro table or temporary table
cursorsetprop() specifies the property settings of the VisualFoxpro table or temporary table
cursortoxml() conversion VI Sualfoxpro temporary table is XML text,
curval() returns field values directly from a table on disk or a remote data source,
dbc() returns the name and path of the current database,
dbf() returns the name of the table opened in the specified workspace, or returns the name of the table according to the table alias,
dbsetprop() gives the current database or the fields and connections in the current database The table or view sets an attribute
deleted() to return a logical value indicating whether the current record is marked with a deletion mark
deleting() creates an index ID with the deleting keyword
dropoffline() discards all modifications to the free view, And put the free view back to the database
eof() determines whether the record pointer position exceeds the current table or the last record in the specified table
fcount() returns the number of fields in the table
field() returns the field name in the table according to the number
filter() returns the table filter expression specified in setfilter command
fldlist() returns the field column specified by setfields command Table, return the field and calculation result field expression
block() attempts to lock the current table or the specified table
for() returns the index filter expression of an opened single index file or index ID
find() if the continue, find, locate or seek command is executed successfully, the return value of the function is & quot; True & quot<
fsize() returns the size of the specified field or file in bytes
getfldstate() returns a value indicating whether the field in the table or temporary table has been edited, whether there are additional records, or whether the deletion status of the record has changed
getextmodified() returns a record number, Corresponding to the next modified record in the buffer table or temporary table,
header() returns the number of bytes occupied by the header of the current or specified table file
idxcollate() returns the sort sequence of index or index ID
indbc() returns & quot; if the specified database object is in the current database; True & quot; ( T. )
indexseek() searches an index table for a record that appears for the first time
isexclusive() judges whether a table or database is opened in exclusive mode
islocked() returns the lock status of the table
isreadonly() judges whether to open the table in read-only mode
isrlocked() returns the lock status of the record
key() returns the lock status of the index ID or index file Index keyword expression
keymatch() searches for an index keyword in the index ID or index file
lookup() searches for the first record in the table whose field value matches the specified expression
update() returns the latest update date of a table
mdx() returns the open. CDX composite index file name according to the specified index number
memlines() returns The number of rows in the comment field
mline() returns the specified row in the comment field in the form of string
ndx() returns the name of a jdx file opened for the current table or the specified table
order() returns the master index file or identifier of the current table or the specified table
primary() checks the index identifier, and if it is the master index identifier, returns & quot; True & quot; ( T. )
reccount() returns the number of records in the current or specified table
recno() returns the current record number in the current or specified table
recsize() returns the size (width) of the records in the table
refresh() refreshes the data in the updatable SQL view
relaxation() returns the relationship expression specified for the table opened in the given workspace
seek() in a built Search the first occurrence position of a record in the indexed table
select() returns the current workspace number or the maximum number of unused workspace
setfldstate() specifies the field status value or deletion status value for the field or record in the table or temporary table
sqlcell() requests to cancel an executing SQL statement
sqllinks() to specify the column name of the data source table And the information about each column is stored in a temporary table of Visual FoxPro
sqlconnect() submits a transaction
sqlconnect() establishes a connection to the data source
sqlconnect() terminates the connection to the data source
sqlexec() sends an SQL statement to the data source for processing
sqlgetprop() returns the current or default setting of an active connection
sql Moreresults() if there are multiple result sets, another result set to the temporary table of VisualFoxpro
sqlcompare() before using sqlexec() to perform remote data operation, You can use this function to prepare the remote data for the command to be executed
sqlcallback() to cancel any changes made ring the current transaction
sqlsetup() to specify the setting of an active connection
sqlstringconnect() to use a connection string to establish a connection with the data source
sqltables() to store the table name in the data source to the temporary table of VisualFoxpro In
sys (14) index expression
sys (21) control index number
sys (22) control identifier name or index name
sys (2011) returns the status of record locking or table locking in the current workspace
sys (2012) returns the remark field block size of the table
sys (2021) filter index expression
sys (2029) returns the value corresponding to the table type
sys (3054) Rushmore optimization Level ·
tag() returns the identification name of the opened. CDX multiple index file, Or return the file name of the opened. IDX single index file
tagcount() returns the composite index file (. CDX) ID and the number of opened single index files (. IDX)
tagno() returns the composite index file (. CDX) ID and the index location of the opened single index file (. IDX)
target() returns the alias of a table, This table is the target of the relationship specified in the into clause of the setreading command.
unique() is used to test whether the index is created in a unique way.
updated() is used to test whether the index is created in the latest read command, Whether the data has been modified
used() determines whether a table has been opened in the specified workspace
xmlcursor() converts XML text to a VisualFoxpro cursor or table

: --- -

Visual FoxPro date and time functions
ctod() converts character expressions to date expressions
cdow() returns the value of the week from a given date or date time expression
cmonth() returns the month name of a given date or date time expression
ctod() converts character expressions to date expressions
ctot() returns a date time value from a character expression
date() returns the current system date of the operating system control, or creates a date value compatible with the year 2000
datetime() returns the current date and time with a date time value, or creates a 2000 compatible date time value
day() returns the number of days in a given day expression or date time expression
dmy() returns a character expression in the format of "day month year" from a date or date time expression (for example, 31 May 1995). The name of the month is not abbreviated
dtoc() returns a character date from a date or date time expression
dtos() returns a string date in yyyymmdd format from a specified date or date time expression
dtot() returns a date time type value from a date type expression
for a given date expression or date time expression, gomonth() returns the date before or after the specified number of months
hour() returns the hour part of a date time expression
mdy() returns the specified date or date time expression in month day year format, where the month name is not abbreviated
minute() returns the minute part of a datetime expression
month() returns the month value of a given date or date time expression
quarter() returns the quarter value in a date or date time expression
sec() returns the second part of the datetime expression
seconds() returns the time since midnight in seconds
sys (1) returns the current system date in the form of date numeric string
sys (2) returns the time since midnight, in seconds
sys (10) converts the (Julian) date to a string
sys (11) converts the date expression or string represented by date format to (Julian) date
time() returns the current system time in 24-hour format and 8-bit string (hour: minute: Second) format
ttoc() returns a character value from a date time expression
ttod() returns a date value from a date time expression
week() returns a number representing the week of the year from a date or date time expression
year() returns the year from the specified date expression

Visual FoxPro character function

alltrim(). Delete the space character before and after the specified character expression
asc() returns the ANSI value of the leftmost character in the character expression
at() returns the first occurrence position of one character expression or remark field in another character expression or remark field
at()_ C() returns the position where a character expression or remark field first appears in another character expression or remark field
atc() returns the position where a character expression or remark field first appears in another character expression or remark field
atcc() returns the position where a character expression or remark field first appears in another character expression or remark field Location
addbs () if necessary, Add a backslash to a path expression
atcline() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
at line() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
between() determines whether the value of an expression is correct Between the values of two other expressions of the same data type,
chr() returns its value according to the specified ANSI numeric code

4. Application of information encryption in network security

Abstract: e to the development of network technology, affecting all aspects of people's lives, people's network activities are more and more frequent, followed by higher and higher security requirements, and higher and higher confidentiality requirements for their own network activities, Ensure that people in the network activities of their own information and some related information confidentiality requirements, to ensure the security and confidentiality of the network. Through the introction of information encryption technology, this paper puts forward an idea of improving RSA algorithm, lists some examples of applying information encryption technology, and emphasizes the importance of information encryption technology in maintaining network security< Key words: information encryption technology, network security, RSA, encryption algorithm

1. Introction

information encryption technology is the core technology of information security. Especially in today's e-commerce, e-cash, digital currency, network banking and other network business rapid rise. How to protect the information security from being stolen, tampered or destroyed has been paid more and more attention. The key to solve this problem is information encryption technology. The so-called encryption is the process of converting the readable information called "plaintext" into "ciphertext"; Decryption is the process of restoring "ciphertext" to "plaintext". Encryption and decryption should use cryptographic algorithm to achieve. Cryptographic algorithm is a computable process used to hide and reveal information. Generally, the more complex the algorithm is, the more secure the ciphertext is. In the encryption technology, the key is essential, the key is to make the cipher algorithm run in a specific way and proce a specific ciphertext value[ 1] The use of encryption algorithm can protect information security from theft, tampering or destruction

2. Information encryption technology

2.1 encryption mode

encryption algorithm can be regarded as a complex function transformation, x = (y, K) x represents ciphertext, that is, the character sequence obtained after encryption, y represents plaintext, that is, the character sequence to be encrypted, and K represents the key. After encryption is completed, the ciphertext can be sent to the receiver through an unsafe channel, Only the receiver with the decryption key can decrypt the ciphertext, that is, the plaintext can be obtained by inverse transformation[ 2]

2.2 encryption algorithm

symmetric algorithm is sometimes called the traditional cryptographic algorithm, that is, the encryption key can be calculated from the decryption key, and vice versa. In most symmetric algorithms, the encryption / decryption key is the same. These algorithms are also called secret key or single key algorithms, which require the sender and receiver to agree on a key before secure communication. The security of symmetric algorithm depends on the key, and revealing the key means that anyone can encrypt / decrypt the message. As long as the communication needs to be kept secret, the key must be kept secret. Therefore, symmetric algorithm means that the encryption and decryption processes use the same key, such as DES, 3DES, AES and other algorithms belong to symmetric algorithm

asymmetric algorithm is also called public key algorithm. The key used for encryption is different from the key used for decryption, and the decryption key cannot be calculated according to the encryption key (at least for a reasonably long time). The reason why it is called public key algorithm is that the encryption key can be made public, that is, the stranger can encrypt the information with the encryption key, but only with the corresponding decryption key can the information be decrypted. But it is difficult to derive the private key from the public key. RSA [1], DSA and other algorithms are asymmetric algorithms, among which RSA is the most widely used, which can not only be used for encryption but also digital signature[ 3]

2.3 an improvement on the asymmetric encryption algorithm RSA

generally, the security of the asymmetric encryption algorithm RSA mainly depends on the large number, but whether it is equal to the decomposition of large number has not been proved in theory, because it is necessary to decompose large number to crack RSA without proof. Therefore, the most obvious attack method is to decompose molus 10, so people choose molus greater than 10100 for security, which undoubtedly reces the event complexity of the algorithm for calculating public key and key< Therefore, based on RSA algorithm, a variant of RSA algorithm is proposed. The specific ideas are as follows:

generation of public encryption transformation ex and secret decryption transformation DX of user X: (1) randomly select n prime numbers P1, P2... PN 2) Calculate NX = P1 * P2... * PN, Ф( nx)=(p1-1)*(p2-1)*……*(rj-1)( 3) Randomly select the integer ex to satisfy (ex, Ф( nx)) =1;( 4) The Euclidean algorithm is used to calculate DX, which satisfies ex * DX ≡ 1 mod Ф( nx);( 5) Disclose NX, ex as ex, and record as ex = & lt; nx,ex>, Confidential P1, P2,..., PN, Ф( Nx) as DX, DX = & lt; p1,p2,……,pn ,dx, Ф( nxj) > Encryption algorithm: C = ex (m) = mex (MOD NX), decryption algorithm: M = DX (c) = CDX (MOD NX). In RSA algorithm, there are two keys: encryption key PK and decryption key SK, and the encryption key is public

the speed of computing 8*8 in binary case is obviously greater than that of 2*2*2*2*2*2 by proving that the speed of the algorithm is higher than that of 2*2*2*2*2*2. This proves the advanced nature of the RSA algorithm. Because of the variant of RSA algorithm or the encryption algorithm based on the original algorithm, the algorithm can be proved by mathematical inction, which basically does not violate the RSA algorithm's Wuan nature. Therefore, the security of RSA algorithm variant is guaranteed

3. Information encryption technology ensures network security

3.1 The Application of information encryption technology in e-commerce

e-commerce is changing people's life and the development process of the whole society, and network trade will cause people's comprehensive innovation in management mode, work and life style, and even business management thinking mode. At the same time, a stable network security environment is crucial to the healthy and sustainable development of e-commerce. The security of e-commerce is mainly the security of network platform and transaction information. The security of transaction information refers to the protection of both sides of the transaction from being damaged and divulged, and the confirmation of the identity of both sides of the transaction[ 4] Therefore, the application of data encryption, digital signature, digital certificate, SSL, set security protocol in e-commerce to ensure the security of e-commerce transaction information, the combination of e-commerce and information encryption technology will promote the stable development of e-commerce

3.2 encrypt anti-virus and anti-virus software. Once the encryption program itself is infected with computer virus, it will not check whether the program or data is encrypted or has digital signature. Every time you start to execute the encryption program, you should check whether it is infected by the virus, and you should also check the files that need to be encrypted and decrypted. This checking mechanism should be confidential. Therefore, encryption technology is also used in some anti-virus or antivirus software[ 5]

3.3 encryption of network database

the public channel and computer storage system in transmission are very fragile. As long as you use a PC to access the Internet, you can steal many other people's useful information, even all kinds of passwords, so it is necessary to take measures to protect the data. Users need to protect the key data effectively. Because the traditional way of database protection is realized by setting password and access rights. The key to solve this problem is to encrypt the data itself, so that even if the data is unfortunately leaked or lost, it is difficult to be deciphered by a third party. The running platform of large database management system is usually windows nt or UNIX, and the security level of these operating systems is usually C1 and C2. They have the security functions of user registration, user identification, arbitrary access control and auditing. Although DBMS adds many security measures on the basis of OS, OS and DBMS still lack effective protection measures for database files. It can be seen that data encryption is necessary for the external or internal security management of the system[ 6]

3.4 the combination of information encryption technology and VPN

nowadays, more and more companies are moving towards collectivization. A company may have subsidiaries or offices in different regions, and each organization has its own LAN, but LAN users want to connect these LANs together to form a WAN. The application of VPN technology can solve this problem, In fact, many companies have done this, but they usually use leased private lines to connect these LANs. Their concern is the security and confidentiality of file transmission. Now routers with information encryption function are everywhere, which makes it possible for people to connect these LANs through the Internet, When the data leaves the local area network where the sender is located, the data is first encrypted by the router connected to the VPN by the client. The data is transmitted in the form of ciphertext on the Internet. When the router reaches the destination local area network, the router will decrypt the data, so that the users in the destination local area network can see the plaintext< This paper introces the related concepts of information encryption technology, gives a simple statement of various encryption algorithms, and puts forward their own improvement suggestions for RSA algorithm. However, e to the limited personal ability, it is insufficient to give a thorough demonstration of the improved RSA algorithm. It also lists several examples of using information encryption technology to maintain network harmony, discusses the importance of information encryption technology to maintain network security, and proves that information encryption technology is an indispensable part of network security.

5. Application of information encryption in network security

Abstract: e to the development of network technology, affecting all aspects of people's lives, people's network activities are more and more frequent, followed by higher and higher security requirements, and higher and higher confidentiality requirements for their own network activities, Ensure that people in the network activities of their own information and some related information confidentiality requirements, to ensure the security and confidentiality of the network. Through the introction of information encryption technology, this paper puts forward an idea of improving RSA algorithm, lists some examples of applying information encryption technology, and emphasizes the importance of information encryption technology in maintaining network security< Key words: information encryption technology, network security, RSA, encryption algorithm

1. Introction

information encryption technology is the core technology of information security. Especially in today's e-commerce, e-cash, digital currency, network banking and other network business rapid rise. How to protect the information security from being stolen, tampered or destroyed has been paid more and more attention. The key to solve this problem is information encryption technology. The so-called encryption is the process of converting the readable information called "plaintext" into "ciphertext"; Decryption is the process of restoring "ciphertext" to "plaintext". Encryption and decryption should use cryptographic algorithm to achieve. Cryptographic algorithm is a computable process used to hide and reveal information. Generally, the more complex the algorithm is, the more secure the ciphertext is. In the encryption technology, the key is essential, the key is to make the cipher algorithm run in a specific way and proce a specific ciphertext value[ 1] The use of encryption algorithm can protect information security from theft, tampering or destruction

2. Information encryption technology

2.1 encryption mode

encryption algorithm can be regarded as a complex function transformation, x = (y, K) x represents ciphertext, that is, the character sequence obtained after encryption, y represents plaintext, that is, the character sequence to be encrypted, and K represents the key. After encryption is completed, the ciphertext can be sent to the receiver through an unsafe channel, Only the receiver with the decryption key can decrypt the ciphertext, that is, the plaintext can be obtained by inverse transformation[ 2]

2.2 encryption algorithm

symmetric algorithm is sometimes called the traditional cryptographic algorithm, that is, the encryption key can be calculated from the decryption key, and vice versa. In most symmetric algorithms, the encryption / decryption key is the same. These algorithms are also called secret key or single key algorithms, which require the sender and receiver to agree on a key before secure communication. The security of symmetric algorithm depends on the key, and revealing the key means that anyone can encrypt / decrypt the message. As long as the communication needs to be kept secret, the key must be kept secret. Therefore, symmetric algorithm means that the encryption and decryption processes use the same key, such as DES, 3DES, AES and other algorithms belong to symmetric algorithm

asymmetric algorithm is also called public key algorithm. The key used for encryption is different from the key used for decryption, and the decryption key cannot be calculated according to the encryption key (at least for a reasonably long time). The reason why it is called public key algorithm is that the encryption key can be made public, that is, the stranger can encrypt the information with the encryption key, but only with the corresponding decryption key can the information be decrypted. But it is difficult to derive the private key from the public key. RSA [1], DSA and other algorithms are asymmetric algorithms, among which RSA is the most widely used, which can not only be used for encryption but also digital signature[ 3]

2.3 an improvement on the asymmetric encryption algorithm RSA

generally, the security of the asymmetric encryption algorithm RSA mainly depends on the large number, but whether it is equal to the decomposition of large number has not been proved in theory, because it is necessary to decompose large number to crack RSA without proof. Therefore, the most obvious attack method is to decompose molus 10, so people choose molus greater than 10100 for security, which undoubtedly reces the event complexity of the algorithm for calculating public key and key< Therefore, based on RSA algorithm, a variant of RSA algorithm is proposed. The specific ideas are as follows:

generation of public encryption transformation ex and secret decryption transformation DX of user X: (1) randomly select n prime numbers P1, P2... PN 2) Calculate NX = P1 * P2... * PN, Ф( nx)=(p1-1)*(p2-1)*……*(rj-1)( 3) Randomly select the integer ex to satisfy (ex, Ф( nx)) =1;( 4) The Euclidean algorithm is used to calculate DX, which satisfies ex * DX ≡ 1 mod Ф( nx);( 5) Disclose NX, ex as ex, and record as ex = & lt; nx,ex>, Confidential P1, P2,..., PN, Ф( Nx) as DX, DX = & lt; p1,p2,……,pn ,dx, Ф( nxj) > Encryption algorithm: C = ex (m) = mex (MOD NX), decryption algorithm: M = DX (c) = CDX (MOD NX). In RSA algorithm, there are two keys: encryption key PK and decryption key SK, and the encryption key is public

the speed of computing 8*8 in binary case is obviously greater than that of 2*2*2*2*2*2 by proving the program. This proves the advanced nature of the RSA algorithm. Because the variant of RSA algorithm is based on the original algorithm, the algorithm can be proved by mathematical inction. Basically, it does not violate the security of RSA algorithm, so it ensures the security of RSA algorithm variants

3. Information encryption technology ensures network security

3.1 The Application of information encryption technology in e-commerce

e-commerce is changing people's life and the development process of the whole society, and network trade will cause people's comprehensive innovation in management mode, work and life style, and even business management thinking mode. At the same time, a stable network security environment is crucial to the healthy and sustainable development of e-commerce. The security of e-commerce is mainly the security of network platform and transaction information. The security of transaction information refers to the protection of both sides of the transaction from being damaged and divulged, and the confirmation of the identity of both sides of the transaction[ 4] Therefore, the application of data encryption, digital signature, digital certificate, SSL, set security protocol in e-commerce to ensure the security of e-commerce transaction information, the combination of e-commerce and information encryption technology will promote the stable development of e-commerce

3.2 encrypt anti-virus and anti-virus software. Once the encryption program itself is infected with computer virus, it will not check whether the program or data is encrypted or has digital signature. Every time you start to execute the encryption program, you should check whether it is infected by the virus, and you should also check the files that need to be encrypted and decrypted. This checking mechanism should be confidential. Therefore, encryption technology is also used in some anti-virus or antivirus software[ 5]

3.3 encryption of network database

the public channel and computer storage system in transmission are very fragile. As long as you use a PC to access the Internet, you can steal many other people's useful information, even all kinds of passwords, so it is necessary to take measures to protect the data. Users need to protect the key data effectively. Because the traditional way of database protection is realized by setting password and access rights. The key to solve this problem is to encrypt the data itself, so that even if the data is unfortunately leaked or lost, it is difficult to be deciphered by a third party. The running platform of large database management system is usually windows nt or UNIX, and the security level of these operating systems is usually C1 and C2. They have the security functions of user registration, user identification, arbitrary access control and auditing. Although DBMS adds many security measures on the basis of OS, OS and DBMS still lack effective protection measures for database files. It can be seen that data encryption is necessary for the external or internal security management of the system[ 6]

3.4 combination of information encryption technology and VPN, The application of VPN technology can solve this problem. In fact, many companies have already done so, but they usually use leased private lines to connect these LANs. Their concern is the security and confidentiality of file transmission. Now routers with information encryption function can be seen everywhere, This makes it possible for people to connect these local area networks through the Internet. When the data leaves the local area network of the sender, the data is first encrypted by the router connected to the VPN by the client. The data is transmitted in the form of ciphertext on the Internet. When it reaches the router of the destination local area network, the router will decrypt the data, In this way, users in the local area network of the target can see the plaintext< This paper introces the related concepts of information encryption technology, gives a simple statement of various encryption algorithms, and puts forward their own improvement suggestions for RSA algorithm. However, e to the limited personal ability, it is insufficient to give a thorough demonstration of the improved RSA algorithm. It also lists several examples of using information encryption technology to maintain network harmony, discusses the importance of information encryption technology to maintain network security, and proves that information encryption technology is an indispensable part of network security< br />

6. Visual FoxPro database function

adatabases() puts the names and paths of all open databases into a memory variable array
objects() puts the named connection name, relationship name, table name or SQL view name in the current database into a memory variable array
afields() stores the structure information of the current table in an array, And returns the number of fields in the table
alias() returns the alias of the current table or the specified workspace
assignments() creates an existing data work period ID array
ataginfo() creates a name containing index and key expression Array of quantity and type information
aused() stores the table alias and workspace in a data working period into the memory variable array
bof() determines whether the current record pointer is in the header
candidate() determines whether the index is a candidate index
cdx() numbers according to the specified index position, Returns the name of the open composite index (. CDX) file
cpdbp() returns the code page used by an open table
create offline() creates a free view from an existing view
cursorgetprop() returns the current property settings of the VisualFoxpro table or temporary table
cursorsetprop() specifies the property settings of the VisualFoxpro table or temporary table
cursortoxml() converts visualf Oxpro temporary table is XML text
curval() returns field values directly from a table on disk or a remote data source
dbc() returns the name and path of the current database
dbf() returns the name of the table opened in the specified workspace, or returns the name of the table according to the table alias
dbsetprop() gives the current database or the fields, named connections The table or view sets an attribute
deleted() to return a logical value indicating whether the current record is marked with a deletion mark
deleting() creates an index ID with the deleting keyword
dropoffline() discards all modifications to the free view, And put the free view back to the database
eof() determines whether the record pointer position exceeds the current table or the last record in the specified table
fcount() returns the number of fields in the table
field() returns the field name in the table according to the number
filter() returns the table filter expression specified in setfilter command
fldlist() for the field list specified by setfields command, Return the field and calculation result field expression
block() attempts to lock the current table or the specified table
for() returns an open single index file or index filter expression of index ID
find() if continue, find, locate or seek command is executed successfully, the return value of the function is & quot; True & quot<
fsize() returns the size of the specified field or file in bytes
getfldstate() returns a value indicating whether the field in the table or temporary table has been edited, whether there are additional records, or whether the deletion status of the record has changed
getextmodified() returns a record number, Corresponding to the next modified record in the buffer table or temporary table,
header() returns the number of bytes occupied by the header of the current or specified table file
idxcollate() returns the sort sequence of index or index ID
indbc() returns & quot; if the specified database object is in the current database; True & quot; ( T. )
indexseek() searches an index table for a record that appears for the first time
isexclusive() judges whether a table or database is opened in exclusive mode
islocked() returns the lock state of the table
isreadonly() judges whether to open the table in read-only mode
isrlocked() returns the lock state of the record
key() returns the index of the index ID or index file Keyword expression
keymatch() searches for an index keyword in the index ID or index file
lookup() searches for the first record whose field value matches the specified expression in the table
update() returns the date of the last update of a table
mdx() returns the open. CDX composite index file name according to the specified index number
memlines() returns remarks Section
mline() returns the specified line in the remarks field in the form of string
ndx() returns the name of an index (jdx) file opened for the current table or the specified table
order() returns the master index file or identifier of the current table or the specified table
primary() checks the index identifier, if it is the master index identifier, it returns & quot; True & quot; ( T. )
reccount() returns the number of records in the current or specified table
recno() returns the current record number in the current or specified table
recsize() returns the size (width) of the records in the table
refresh() refreshes the data in the updatable SQL view
relaxation() returns the relationship expression specified for the table opened in the given workspace
seek() in an established query Search for the first occurrence position of a record in the referenced table
select() returns the current workspace number or the maximum number of unused workspaces
setfldstate() specifies the field status value or deletion status value for the field or record in the table or temporary table
sqlcall() requests to cancel an executing SQL statement
sqlcalls() to specify the column name and about of the data source table The information of each column is stored in a VisualFoxpro temporary table
sqlconnect() submits a transaction
sqlconnect() establishes a connection to the data source
sqlconnect() terminates the connection with the data source
sqlexec() sends an SQL statement to the data source for processing
sqlgetprop() returns the current or default setting of an active connection
sqlmoreresults() If there are multiple result sets, another result set to the temporary table of VisualFoxpro
sqlprepare() before using sqlexec() to perform remote data operation, You can use this function to prepare the remote data for the command to be executed
sqlcallback() to cancel any changes made ring the current transaction
sqlsetup() to specify the setting of an active connection
sqlstringconnect() to use a connection string to establish a connection with the data source
sqltables() to store the table name in the data source in the temporary table of VisualFoxpro
sqltables() />Sys (14) index expression
sys (21) control index number
sys (22) control identifier name or index name
sys (2011) returns the status of record locking or table locking in the current workspace
sys (2012) returns the remark field block size of the table
sys (2021) selects index expression
sys (2029) returns the value corresponding to the table type
sys (3054) Rushmore optimization level · < br />Tag() returns the identification name of the opened. CDX multiple index file, Or return the file name of the opened. IDX single index file
tagcount() returns the composite index file (. CDX) ID and the number of opened single index files (. IDX)
tagno() returns the composite index file (. CDX) ID and the index location of the opened single index file (. IDX)
target() returns the alias of a table, This table is the target of the relationship specified in the into clause of the setreading command.
unique() is used to test whether the index is created in a unique way.
updated() is used to test whether the index is created in the latest read command, Whether the data has been modified
used() determines whether a table is opened in the specified workspace
xmlcursor() converts the XML text to a VisualFoxpro cursor or table

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
cdow() returns the value of the week from a given date or date time expression
cmonth() returns the month name of a given date or date time expression
ctod() converts character expressions to date expressions
ctot() returns a date time value from a character expression
date() returns the current system date of the operating system control, or creates a date value compatible with the year 2000
datetime() returns the current date and time with a date time value, or creates a 2000 compatible date time value
day() returns the number of days in a given day expression or date time expression
dmy() returns a character expression in the format of "day month year" from a date or date time expression (for example, 31 May 1995). The name of the month is not abbreviated
dtoc() returns a character date from a date or date time expression
dtos() returns a string date in yyyymmdd format from a specified date or date time expression
dtot() returns a date time type value from a date type expression
for a given date expression or date time expression, gomonth() returns the date before or after the specified number of months
hour() returns the hour part of a date time expression
mdy() returns the specified date or date time expression in month day year format, where the month name is not abbreviated
minute() returns the minute part of a datetime expression
month() returns the month value of a given date or date time expression
quarter() returns the quarter value in a date or date time expression
sec() returns the second part of the datetime expression
seconds() returns the time since midnight in seconds
sys (1) returns the current system date in the form of date numeric string
sys (2) returns the time since midnight, in seconds
sys (10) converts the (Julian) date to a string
sys (11) converts the date expression or string represented by date format to (Julian) date
time() returns the current system time in 24-hour format and 8-bit string (hour: minute: Second) format
ttoc() returns a character value from a date time expression
ttod() returns a date value from a date time expression
week() returns a number representing the week of the year from a date or date time expression
year() returns the year from the specified date expression

Visual FoxPro character function

alltrim(). Delete the space character before and after the specified character expression
asc() returns the ANSI value of the leftmost character in the character expression
at() returns the first occurrence position of one character expression or remark field in another character expression or remark field
at()_ C() returns the position where a character expression or remark field first appears in another character expression or remark field
atc() returns the position where a character expression or remark field first appears in another character expression or remark field
atcc() returns the position where a character expression or remark field first appears in another character expression or remark field Current location
addbs () if necessary, Add a backslash to a path expression
atcline() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
at line() returns the line number of the first occurrence of a character expression or remark field in another character expression or remark field
between() determines the value of an expression No, between the values of two other expressions of the same data type,
chr() returns its corresponding characters according to the specified ANSI numeric code,
chrtran() matches the characters in the first character expression with those in the second expression

7. Unknown_Error

8. Both can be used. The input data of the first execution needs a delimiter, and the input data of the second execution does not need a delimiter. It is better to use "accept" please input string "to x,
and then follow a command to change all the input string letters into uppercase. x=upper(x)

9. You can refer to the relevant information I sent to your email.