59 lines
1.9 KiB
C
59 lines
1.9 KiB
C
|
#ifndef __CRYPTO_H__
|
||
|
|
#define __CRYPTO_H__
|
||
|
|
|
||
|
|
/** Length of key not sufficient. */
|
||
|
|
#define E_KEY_TOO_SHORT 1
|
||
|
|
|
||
|
|
/** Key contains illegal characters. */
|
||
|
|
#define E_KEY_ILLEGAL_CHAR 2
|
||
|
|
|
||
|
|
/** Message contains illegal characters. */
|
||
|
|
#define E_MESSAGE_ILLEGAL_CHAR 3
|
||
|
|
|
||
|
|
/** Cypher text contains illegal characters. */
|
||
|
|
#define E_CYPHER_ILLEGAL_CHAR 4
|
||
|
|
|
||
|
|
#define KEY_CHARACTERS "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
|
||
|
|
#define MESSAGE_CHARACTERS "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
|
||
|
|
#define CYPHER_CHARACTERS "@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_"
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Key used in de- and encryption.
|
||
|
|
*/
|
||
|
|
typedef struct {
|
||
|
|
int type; /* Type of the key. */
|
||
|
|
char* chars; /* Key characters. */
|
||
|
|
} KEY;
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Encrypt the given text and return the encrypted version. The input text
|
||
|
|
* may only contain the letters A-Z. No space or other characters are
|
||
|
|
* allowed. In case of illegal characters in the text, the function
|
||
|
|
* returns E_MESSAGE_ILLEGAL_CHAR. The key must contain a valid character set
|
||
|
|
* and have a sufficient length. For XOR encryption only the characters
|
||
|
|
* A-Z are valid in the key. The key must have at least a length of 1.
|
||
|
|
*
|
||
|
|
* @param key Key to be used for the encryption
|
||
|
|
* @param input Clear text
|
||
|
|
* @param output Encrypted text
|
||
|
|
* @return 0 on success, otherwise error code
|
||
|
|
*/
|
||
|
|
int encrypt(KEY key, const char* input, char* output);
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Decrypt the given text and return the decrypted version. The cypher text
|
||
|
|
* may only contain the characters defined as output of the encrypt function.
|
||
|
|
* For other characters the function will return E_CYPHER_ILLEGAL_CHAR.
|
||
|
|
* The key must contain a valid character set
|
||
|
|
* and have a sufficient length. For XOR encryption only the characters
|
||
|
|
* A-Z are valid in the key. The key must have at least a length of 1.
|
||
|
|
*
|
||
|
|
* @param key Key to be used for the decryption
|
||
|
|
* @param cypherText Cypher text
|
||
|
|
* @param output Decrypted text
|
||
|
|
* @return 0 on success, otherwise error code
|
||
|
|
*/
|
||
|
|
int decrypt(KEY key, const char* cypherText, char* output);
|
||
|
|
|
||
|
|
#endif /* __CRYPTO_H__ */
|