silccipher.h
- Author: Pekka Riikonen <priikone@poseidon.pspt.fi>
+ Author: Pekka Riikonen <priikone@silcnet.org>
- Copyright (C) 1997 - 2001 Pekka Riikonen
+ Copyright (C) 1997 - 2008 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 Free Software Foundation; either version 2 of the License, or
- (at your option) any later version.
-
+ the Free Software Foundation; version 2 of the License.
+
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
*/
+/****h* silccrypt/SILC Cipher Interface
+ *
+ * DESCRIPTION
+ *
+ * This is the interface for cipher functions. It provides cipher
+ * registering and unregistering routines, encryption and decryption
+ * routines.
+ *
+ ***/
+
#ifndef SILCCIPHER_H
#define SILCCIPHER_H
-/*
- SILC Cipher object.
-
- Default SILC cipher object to represent any cipher. The function
- pointers are the stub functions for each implemented cipher. Following
- short description of the fields:
-
- char *name
+/* Forward declarations */
+typedef struct SilcCipherObjectStruct SilcCipherObject;
- Logical name of the cipher.
+/****s* silccrypt/SilcCipherAPI/SilcCipher
+ *
+ * NAME
+ *
+ * typedef struct SilcCipherStruct *SilcCipher;
+ *
+ * DESCRIPTION
+ *
+ * This context is the actual cipher context and is allocated
+ * by silc_cipher_alloc and given as argument usually to all
+ * silc_cipher _* functions. It is freed by the silc_cipher_free
+ * function.
+ *
+ ***/
+typedef struct SilcCipherStruct *SilcCipher;
- uint32 block_len
+/****d* silccrypt/SilcCipherAPI/SilcCipherMode
+ *
+ * NAME
+ *
+ * typedef enum { ... } SilcCipherMode;
+ *
+ * DESCRIPTION
+ *
+ * Cipher modes. Notes about cipher modes and implementation:
+ *
+ * SILC_CIPHER_MODE_CBC
+ *
+ * The Cipher-block Chaining mode. 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.
+ *
+ * SILC_CIPHER_MODE_CTR
+ *
+ * The Counter mode. 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 counter
+ * mode expects MSB first ordered counter. Note also, the counter is
+ * incremented when silc_cipher_encrypt is called for the first time,
+ * before encrypting.
+ *
+ * SILC_CIPHER_MODE_CFB
+ *
+ * The Cipher Feedback mode. The CFB mode is normal cipher feedback mode.
+ * The CFB 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 stream are used next time silc_cipher_encrypt is
+ * called. If silc_cipher_set_iv is called it will reset the feedback
+ * for a new block (discarding any remaining bits from previous stream).
+ *
+ * SILC_CIPHER_MODE_OFB
+ *
+ * The Output Feedback mode.
+ *
+ * SILC_CIPHER_MODE_ECB
+ *
+ * The Electronic Codebook mode. This mode does not provide sufficient
+ * security and should not be used.
+ *
+ * Each mode modifies the IV (initialization vector) of the cipher when
+ * silc_cipher_encrypt or silc_cipher_decrypt is called. The IV may be
+ * set/reset by calling silc_cipher_set_iv and the current IV can be
+ * retrieved by calling silc_cipher_get_iv.
+ *
+ * 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;
+/***/
- Block size of the cipher.
-
- uint32 key_len
-
- Length of the key of the cipher (in bits).
-
-*/
-typedef struct {
- char *name;
- uint32 block_len;
- uint32 key_len;
-
- bool (*set_key)(void *, const unsigned char *, uint32);
- bool (*set_key_with_string)(void *, const unsigned char *, uint32);
- bool (*encrypt)(void *, const unsigned char *, unsigned char *,
- uint32, unsigned char *);
- bool (*decrypt)(void *, const unsigned char *, unsigned char *,
- uint32, unsigned char *);
- uint32 (*context_len)();
-} SilcCipherObject;
-
-#define SILC_CIPHER_MAX_IV_SIZE 16
-
-/* The main SilcCipher structure. Use SilcCipher instead of SilcCipherStruct.
- Also remember that SilcCipher is a pointer. */
-typedef struct SilcCipherStruct {
- SilcCipherObject *cipher;
- void *context;
- unsigned char iv[SILC_CIPHER_MAX_IV_SIZE];
- void (*set_iv)(struct SilcCipherStruct *, const unsigned char *);
- void (*get_iv)(struct SilcCipherStruct *, unsigned char *);
- uint32 (*get_key_len)(struct SilcCipherStruct *);
- uint32 (*get_block_len)(struct SilcCipherStruct *);
-} *SilcCipher;
+#define SILC_CIPHER_MAX_IV_SIZE 16 /* Maximum IV size */
+#define SILC_DEFAULT_CIPHER "aes-256-cbc" /* Default cipher */
/* Marks for all ciphers in silc. This can be used in silc_cipher_unregister
to unregister all ciphers at once. */
#define SILC_ALL_CIPHERS ((SilcCipherObject *)1)
+#include "silccipher_i.h"
+
/* Static list of ciphers for silc_cipher_register_default(). */
-extern SilcCipherObject silc_default_ciphers[];
-
-/* 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
- is appended into these names and used to the get correct symbol out
- 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_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) \
-bool silc_##cipher##_set_key(void *context, \
- const unsigned char *key, \
- uint32 keylen)
-#define SILC_CIPHER_API_SET_KEY_WITH_STRING(cipher) \
-bool silc_##cipher##_set_key_with_string(void *context, \
- const unsigned char *string, \
- uint32 stringlen)
-#define SILC_CIPHER_API_ENCRYPT_CBC(cipher) \
-bool silc_##cipher##_encrypt_cbc(void *context, \
- const unsigned char *src, \
- unsigned char *dst, \
- uint32 len, \
- unsigned char *iv)
-#define SILC_CIPHER_API_DECRYPT_CBC(cipher) \
-bool silc_##cipher##_decrypt_cbc(void *context, \
- const unsigned char *src, \
- unsigned char *dst, \
- uint32 len, \
- unsigned char *iv)
-#define SILC_CIPHER_API_CONTEXT_LEN(cipher) \
-uint32 silc_##cipher##_context_len()
+extern DLLAPI const SilcCipherObject silc_default_ciphers[];
/* Prototypes */
-bool silc_cipher_register(SilcCipherObject *cipher);
-bool silc_cipher_unregister(SilcCipherObject *cipher);
-bool silc_cipher_register_default(void);
-bool silc_cipher_alloc(const unsigned char *name, SilcCipher *new_cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_register
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_register(const SilcCipherObject *cipher);
+ *
+ * DESCRIPTION
+ *
+ * Register a new cipher into SILC. This is used at the initialization of
+ * the SILC. This function allocates a new object for the cipher to be
+ * registered. Therefore, if memory has been allocated for the object sent
+ * as argument it has to be free'd after this function returns succesfully.
+ *
+ ***/
+SilcBool silc_cipher_register(const SilcCipherObject *cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_unregister
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_unregister(SilcCipherObject *cipher);
+ *
+ * DESCRIPTION
+ *
+ * Unregister a cipher from the SILC.
+ *
+ ***/
+SilcBool silc_cipher_unregister(SilcCipherObject *cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_register_default
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_register_default(void);
+ *
+ * DESCRIPTION
+ *
+ * Function that registers all the default ciphers (all builtin ciphers).
+ * The application may use this to register the default ciphers if specific
+ * ciphers in any specific order is not wanted.
+ *
+ ***/
+SilcBool silc_cipher_register_default(void);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_unregister_all
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_unregister_all(void);
+ *
+ * DESCRIPTION
+ *
+ * Unregisters all ciphers.
+ *
+ ***/
+SilcBool silc_cipher_unregister_all(void);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_alloc
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_alloc(const char *name,
+ * SilcCipher *new_cipher);
+ *
+ * DESCRIPTION
+ *
+ * Allocates a new SILC cipher object. Function returns TRUE on succes
+ * and FALSE on error. The allocated cipher is returned in new_cipher
+ * argument. The caller must set the key to the cipher after this
+ * function has returned by calling the silc_cipher_set_key.
+ *
+ * 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:
+ *
+ ***/
+SilcBool silc_cipher_alloc(const char *name, SilcCipher *new_cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_alloc
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_alloc_full(const char *alg_name,
+ * SilcUInt32 key_len,
+ * SilcCipherMode mode,
+ * SilcCipher *new_cipher);
+ * DESCRIPTION
+ *
+ * Same as silc_cipher_alloc but takes the cipher algorithm name,
+ * key length and mode as separate arguments.
+ *
+ ***/
+SilcBool silc_cipher_alloc_full(const char *alg_name, SilcUInt32 key_len,
+ SilcCipherMode mode, SilcCipher *new_cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_free
+ *
+ * SYNOPSIS
+ *
+ * void silc_cipher_free(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Frees the given cipher.
+ *
+ ***/
void silc_cipher_free(SilcCipher cipher);
-bool silc_cipher_is_supported(const unsigned char *name);
-char *silc_cipher_get_supported(void);
-bool silc_cipher_encrypt(SilcCipher cipher, const unsigned char *src,
- unsigned char *dst, uint32 len,
- unsigned char *iv);
-bool silc_cipher_decrypt(SilcCipher cipher, const unsigned char *src,
- unsigned char *dst, uint32 len,
- unsigned char *iv);
-bool silc_cipher_set_key(SilcCipher cipher, const unsigned char *key,
- uint32 keylen);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_is_supported
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_is_supported(const char *name);
+ *
+ * DESCRIPTION
+ *
+ * Returns TRUE if cipher `name' is supported.
+ *
+ ***/
+SilcBool silc_cipher_is_supported(const char *name);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_supported
+ *
+ * SYNOPSIS
+ *
+ * char *silc_cipher_get_supported(SilcBool only_registered);
+ *
+ * DESCRIPTION
+ *
+ * Returns comma separated list of supported ciphers. If `only_registered'
+ * is TRUE only ciphers explicitly registered with silc_cipher_register
+ * are returned. If FALSE, then all registered and default builtin
+ * ciphers are returned. However, if there are no registered ciphers
+ * and `only_registered' is TRUE, the builtin ciphers are returned.
+ *
+ ***/
+char *silc_cipher_get_supported(SilcBool only_registered);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_encrypt
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_encrypt(SilcCipher cipher,
+ * const unsigned char *src,
+ * unsigned char *dst, SilcUInt32 len,
+ * unsigned char *iv);
+ *
+ * DESCRIPTION
+ *
+ * Encrypts data from `src' into `dst' with the specified cipher and
+ * Initial Vector (IV). If the `iv' is NULL then the cipher's internal
+ * IV is used. The `src' and `dst' maybe same buffer.
+ *
+ ***/
+SilcBool silc_cipher_encrypt(SilcCipher cipher, const unsigned char *src,
+ unsigned char *dst, SilcUInt32 len,
+ unsigned char *iv);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_decrypt
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_decrypt(SilcCipher cipher,
+ * const unsigned char *src,
+ * unsigned char *dst, SilcUInt32 len,
+ * unsigned char *iv);
+ *
+ * DESCRIPTION
+ *
+ * Decrypts data from `src' into `dst' with the specified cipher and
+ * Initial Vector (IV). If the `iv' is NULL then the cipher's internal
+ * IV is used. The `src' and `dst' maybe same buffer.
+ *
+ ***/
+SilcBool silc_cipher_decrypt(SilcCipher cipher, const unsigned char *src,
+ unsigned char *dst, SilcUInt32 len,
+ unsigned char *iv);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_set_key
+ *
+ * SYNOPSIS
+ *
+ * SilcBool silc_cipher_set_key(SilcCipher cipher, const unsigned char *key,
+ * SilcUInt32 bit_keylen, SilcBool encryption);
+ *
+ * DESCRIPTION
+ *
+ * Sets the key for the cipher. The `keylen' is the key length in
+ * 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 bit_keylen, SilcBool encryption);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_set_iv
+ *
+ * SYNOPSIS
+ *
+ * void silc_cipher_set_iv(SilcCipher cipher, const unsigned char *iv);
+ *
+ * DESCRIPTION
+ *
+ * Sets the IV (initialization vector) for the cipher. The `iv' must be
+ * 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.
+ *
+ * If the encryption mode is CFB (cipher feedback) this also resets the
+ * the feedback stream for a new block. This is done also if `iv' is NULL.
+ *
+ ***/
void silc_cipher_set_iv(SilcCipher cipher, const unsigned char *iv);
-void silc_cipher_get_iv(SilcCipher cipher, unsigned char *iv);
-uint32 silc_cipher_get_key_len(SilcCipher cipher);
-uint32 silc_cipher_get_block_len(SilcCipher cipher);
-#endif
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_iv
+ *
+ * SYNOPSIS
+ *
+ * unsigned char *silc_cipher_get_iv(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the IV (initial vector) of the cipher. The returned
+ * 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);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_key_len
+ *
+ * SYNOPSIS
+ *
+ * SilcUInt32 silc_cipher_get_key_len(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the key length of the cipher in bits.
+ *
+ ***/
+SilcUInt32 silc_cipher_get_key_len(SilcCipher cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_block_len
+ *
+ * SYNOPSIS
+ *
+ * SilcUInt32 silc_cipher_get_block_len(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the block size of the cipher in bytes.
+ *
+ ***/
+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);
+ *
+ * DESCRIPTION
+ *
+ * Returns the full name of the cipher (eg. 'aes-256-ctr').
+ *
+ ***/
+const char *silc_cipher_get_name(SilcCipher cipher);
+
+/****f* silccrypt/SilcCipherAPI/silc_cipher_get_alg_name
+ *
+ * SYNOPSIS
+ *
+ * const char *silc_cipher_get_alg_name(SilcCipher cipher);
+ *
+ * DESCRIPTION
+ *
+ * Returns the algorithm name of the cipher (eg. 'aes').
+ *
+ ***/
+const char *silc_cipher_get_alg_name(SilcCipher cipher);
+
+/****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 */
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