Author: Pekka Riikonen <priikone@silcnet.org>
- Copyright (C) 1997 - 2005 Pekka Riikonen
+ Copyright (C) 1997 - 2007 Pekka Riikonen
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
/* The default SILC Cipher object to represent any cipher in SILC. */
typedef struct {
char *name;
- SilcUInt32 block_len;
- SilcUInt32 key_len;
-
- SilcBool (*set_key)(void *, const unsigned char *, SilcUInt32);
- SilcBool (*set_key_with_string)(void *, const unsigned char *, SilcUInt32);
+ SilcBool (*set_key)(void *, const unsigned char *, SilcUInt32, SilcBool);
+ void (*set_iv)(void *, const unsigned char *);
SilcBool (*encrypt)(void *, const unsigned char *, unsigned char *,
- SilcUInt32, unsigned char *);
+ SilcUInt32, unsigned char *);
SilcBool (*decrypt)(void *, const unsigned char *, unsigned char *,
- SilcUInt32, unsigned char *);
+ SilcUInt32, unsigned char *);
SilcUInt32 (*context_len)();
+ unsigned int key_len : 10;
+ unsigned int block_len : 8;
+ unsigned int iv_len : 8;
+ unsigned int mode : 6;
} SilcCipherObject;
#define SILC_CIPHER_MAX_IV_SIZE 16
/* Default cipher in the SILC protocol */
#define SILC_DEFAULT_CIPHER "aes-256-cbc"
-
/* Macros */
/* Function names in SILC Crypto modules. The name of the cipher
of the module. All SILC Crypto API compliant modules must support
these function names (use macros below to assure this). */
#define SILC_CIPHER_SIM_SET_KEY "set_key"
-#define SILC_CIPHER_SIM_SET_KEY_WITH_STRING "set_key_with_string"
-#define SILC_CIPHER_SIM_ENCRYPT_CBC "encrypt_cbc"
-#define SILC_CIPHER_SIM_DECRYPT_CBC "decrypt_cbc"
+#define SILC_CIPHER_SIM_ENCRYPT "encrypt"
+#define SILC_CIPHER_SIM_DECRYPT "decrypt"
#define SILC_CIPHER_SIM_CONTEXT_LEN "context_len"
/* These macros can be used to implement the SILC Crypto API and to avoid
errors in the API these macros should be used always. */
-#define SILC_CIPHER_API_SET_KEY(cipher) \
-SilcBool silc_##cipher##_set_key(void *context, \
- const unsigned char *key, \
- SilcUInt32 keylen)
-#define SILC_CIPHER_API_SET_KEY_WITH_STRING(cipher) \
-SilcBool silc_##cipher##_set_key_with_string(void *context, \
- const unsigned char *string, \
- SilcUInt32 stringlen)
-#define SILC_CIPHER_API_ENCRYPT_CBC(cipher) \
-SilcBool silc_##cipher##_encrypt_cbc(void *context, \
+#define SILC_CIPHER_API_SET_KEY(cipher) \
+SilcBool silc_##cipher##_set_key(void *context, \
+ const unsigned char *key, \
+ SilcUInt32 keylen, \
+ SilcBool encryption)
+#define SILC_CIPHER_API_SET_IV(cipher) \
+void silc_##cipher##_set_iv(void *context, \
+ const unsigned char *iv)
+#define SILC_CIPHER_API_ENCRYPT(cipher) \
+SilcBool silc_##cipher##_encrypt(void *context, \
const unsigned char *src, \
- unsigned char *dst, \
+ unsigned char *dst, \
SilcUInt32 len, \
- unsigned char *iv)
-#define SILC_CIPHER_API_DECRYPT_CBC(cipher) \
-SilcBool silc_##cipher##_decrypt_cbc(void *context, \
- const unsigned char *src, \
+ unsigned char *iv)
+#define SILC_CIPHER_API_DECRYPT(cipher) \
+SilcBool silc_##cipher##_decrypt(void *context, \
+ const unsigned char *src, \
unsigned char *dst, \
SilcUInt32 len, \
unsigned char *iv)
-
-
-#define SILC_CIPHER_API_CONTEXT_LEN(cipher) \
+#define SILC_CIPHER_API_CONTEXT_LEN(cipher) \
SilcUInt32 silc_##cipher##_context_len()
+/****d* silccrypt/SilcCipherAPI/SilcCipherMode
+ *
+ * NAME
+ *
+ * typedef enum { ... } SilcCipherMode;
+ *
+ * DESCRIPTION
+ *
+ * Cipher modes.
+ *
+ * SOURCE
+ */
+typedef enum {
+ SILC_CIPHER_MODE_ECB = 1, /* ECB mode */
+ SILC_CIPHER_MODE_CBC = 2, /* CBC mode */
+ SILC_CIPHER_MODE_CTR = 3, /* CTR mode */
+ SILC_CIPHER_MODE_CFB = 4, /* CFB mode */
+ SILC_CIPHER_MODE_OFB = 5, /* OFB mode */
+} SilcCipherMode;
+/***/
/* Prototypes */
* SYNOPSIS
*
* SilcBool silc_cipher_alloc(const unsigned char *name,
- * SilcCipher *new_cipher);
+ * SilcCipher *new_cipher);
*
* DESCRIPTION
*
* caller must set the key to the cipher after this function has returned
* by calling the ciphers set_key function.
*
+ * The following ciphers are supported:
+ *
+ * aes-256-ctr AES-256, Counter mode
+ * aes-192-ctr AES-192, Counter mode
+ * aes-128-ctr AES,128, Counter mode
+ * aes-256-cbc AES-256, Cipher block chaining mode
+ * aes-192-cbc AES-192, Cipher block chaining mode
+ * aes-128-cbc AES,128, Cipher block chaining mode
+ * twofish-256-cbc Twofish-256, Cipher block chaining mode
+ * twofish-192-cbc Twofish-192, Cipher block chaining mode
+ * twofish-128-cbc Twofish-128, Cipher block chaining mode
+ *
+ * Notes about modes:
+ *
+ * The CTR is normal counter mode. The CTR mode does not require the
+ * plaintext length to be multiple by the cipher block size. If the last
+ * plaintext block is shorter the remaining bits of the key stream are
+ * used next time silc_cipher_encrypt is called. If silc_cipher_set_iv
+ * is called it will reset the counter for a new block (discarding any
+ * remaining bits from previous key stream).
+ *
+ * The CBC is mode is a standard CBC mode. The plaintext length must be
+ * multiple by the cipher block size. If it isn't the plaintext must be
+ * padded.
+ *
***/
SilcBool silc_cipher_alloc(const unsigned char *name, SilcCipher *new_cipher);
* SYNOPSIS
*
* SilcBool silc_cipher_set_key(SilcCipher cipher, const unsigned char *key,
- * SilcUInt32 keylen);
+ * SilcUInt32 keylen, SilcBool encryption);
*
* DESCRIPTION
*
* Sets the key for the cipher. The `keylen' is the key length in
- * bits.
+ * bits. If the `encryption' is TRUE the key is for encryption, if FALSE
+ * the key is for decryption.
*
***/
SilcBool silc_cipher_set_key(SilcCipher cipher, const unsigned char *key,
- SilcUInt32 keylen);
+ SilcUInt32 keylen, SilcBool encryption);
/****f* silccrypt/SilcCipherAPI/silc_cipher_set_iv
*
* DESCRIPTION
*
* Sets the IV (initial vector) for the cipher. The `iv' must be
- * the size of the block size of the cipher.
+ * the size of the block size of the cipher. If `iv' is NULL this
+ * does not do anything.
+ *
+ * If the encryption mode is CTR (Counter mode) this also resets the
+ * the counter for a new block. This is done also if `iv' is NULL.
*
***/
void silc_cipher_set_iv(SilcCipher cipher, const unsigned char *iv);
* DESCRIPTION
*
* Returns the IV (initial vector) of the cipher. The returned
- * pointer must not be freed by the caller.
+ * pointer must not be freed by the caller. If the caller modifies
+ * the returned pointer the IV inside cipher is also modified.
*
***/
unsigned char *silc_cipher_get_iv(SilcCipher cipher);
***/
SilcUInt32 silc_cipher_get_block_len(SilcCipher cipher);
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_iv_len
+ *
+ * SYNOPSIS
+ *
+ * SilcUInt32 silc_cipher_get_iv_len(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the IV length of the cipher in bytes.
+ *
+ ***/
+SilcUInt32 silc_cipher_get_iv_len(SilcCipher cipher);
+
/****f* silccrypt/SilcCipherAPI/silc_cipher_get_name
*
* SYNOPSIS
***/
const char *silc_cipher_get_name(SilcCipher cipher);
-#endif
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_mode
+ *
+ * SYNOPSIS
+ *
+ * SilcCipherMode silc_cipher_get_mode(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the cipher mode.
+ *
+ ***/
+SilcCipherMode silc_cipher_get_mode(SilcCipher cipher);
+
+#endif /* SILCCIPHER_H */