Perform DES symmetric encryption.
Syntax:
des(input,key,iv;charset)
Note:
The function uses DES symmetric encryption algorithm to encrypt/decrypt parameter input.
key is the access key. Initiation vector parameter iv is only needed when CBC encryption mode is used; use ECB encryption mode by default when @c option representing the CBC mode is absent.
Usually parameters input, key and iv are BLOB type; the function also supports automatic string encoding.
key must have 8 bytes at least. Note that it must have 8 bytes after encoding if the to-be-encrypted value is a string.
iv must have 8 bytes at least. Note that it must have 8 bytes after encoding if the to-be-encrypted value is a string.
Parameter:
|
input |
Data to be encrypted/decrypted |
|
key |
Access key |
|
iv |
Initiation vector |
|
charset |
Character set, which is utf-8 by default; No need to set up this parameter when both input and key are BLOB type |
Option:
|
@d |
Perform decryption. Values of parameters key, iv and charset should be same for encryption and decryption |
|
@c |
Use CBC encryption mode; use the default mode when parameter iv is absent |
|
@n |
Use NoPadding; in this case the number of bytes in input must be the integer multiple of 8, otherwise error will be reported |
Return value:
BLOB value
Example:
Encryption and decryption:
|
|
A |
|
|
1 |
Hello World! |
|
|
2 |
v7wz+QhT |
|
|
3 |
=charencode(A1; "GBK") |
Generate a BLOB value using A1’s string. |
|
4 |
=charencode(A2; "GBK") |
Generate a 8-byte BLOB value using A2’s string. |
|
5 |
=des(A3,A4) |
Encrypt A3 using DES symmetric encryption mode while setting up A4 as the access key, and return a BLOB value. |
|
6 |
=des@d(A5,A4) |
Use @d option to decrypt A5 – the access key must be consistent with that in A5’s encryption, and return a BLOB value. |
|
7 |
=charencode(A6;"GBK") |
Generate a string using A6’s BLOB value and return the result: Hello World! |
CBC encryption mode:
|
|
A |
|
|
1 |
Hello World! |
|
|
2 |
v7wz+QhTvq |
|
|
3 |
abcdefgh |
|
|
4 |
=des@c(A1,A2,A3;"utf-8") |
@c option enables using the CBC encryption mode; A3 is the initiation vector and the character set is utf-8; the encoded access key has 10 bytes and the initiation vector has 8 bytes. |
|
5 |
=des@cd(A4,A2,A3) |
Decrypt A4 – access key and initiation vector must be consistent with those in A4’s encryption and use the default utf-8 as parameter charset is absent, and return a BLOB value. |
|
6 |
=charencode(A5;"utf-8") |
Generate a string using A5’s BLOB value and return the result: Hello World! |
NoPadding:
|
|
A |
|
|
1 |
Hello!! |
|
|
2 |
v7w |
|
|
3 |
=charencode(A1;"unicode" ) |
Generate a 16-byte BLOB value using A1’s string. |
|
4 |
=charencode(A2;"unicode") |
Generate an 8-byte BLOB value using A2’s string. |
|
5 |
=des@n(A3,A4) |
@n option enables NoPadding; in this case the number of bytes in parameter input must be the integer multiple of 8; return a BLOB value. |
|
6 |
=des@nd(A5,A4) |
Decrypt A5. |
|
7 |
=charencode(A6;"unicode") |
Generate a string using A6’s BLOB value and return same result as A1. |