5 Author: Pekka Riikonen <priikone@silcnet.org>
7 Copyright (C) 1997 - 2002 Pekka Riikonen
9 This program is free software; you can redistribute it and/or modify
10 it under the terms of the GNU General Public License as published by
11 the Free Software Foundation; version 2 of the License.
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
20 /****h* silccore/SILC Message Interface
24 * This interface includes the implementation of the Message Payload that
25 * is used to send private messages and channel messages.
27 * This interface defines also the SILC_MESSAGE_FLAG_SIGNED Payload,
28 * which defines how channel messages and private messages can be digitally
29 * signed. This interface provides the payload parsing, encoding,
30 * signature computing and signature verification routines.
37 /****s* silccore/SilcMessageAPI/SilcMessagePayload
41 * typedef struct SilcMessagePayloadStruct *SilcMessagePayload;
46 * This context is the actual Message Payload and is allocated
47 * by silc_message_payload_parse and given as argument usually
48 * to all silc_message_* functions. It is freed by the
49 * silc_message_payload_free function.
52 typedef struct SilcMessagePayloadStruct *SilcMessagePayload;
54 /****s* silccore/SilcMessageAPI/SilcMessageSignedPayload
58 * typedef struct SilcMessageSignedPayloadStruct *SilcMessageSignedPayload;
63 * This context represents the SILC_MESSAGE_FLAG_SIGNED Payload which
64 * is used with channel messages and private messages to indicate that
65 * the message is digitally signed. This payload may include the
66 * message sender's public key and it includes the digital signature.
67 * This payload MUST NOT be used in any other context except with
68 * channel and private message sending and reception.
71 typedef struct SilcMessageSignedPayloadStruct *SilcMessageSignedPayload;
73 /****d* silccore/SilcMessageAPI/SilcMessageFlags
77 * typedef SilcUInt16 SilcMessageFlags;
81 * The message flags type definition and the message flags. The
82 * message flags are used to indicate some status of the message.
86 typedef SilcUInt16 SilcMessageFlags;
88 /* The message flags */
89 #define SILC_MESSAGE_FLAG_NONE 0x0000 /* No flags */
90 #define SILC_MESSAGE_FLAG_AUTOREPLY 0x0001 /* Automatically replied */
91 #define SILC_MESSAGE_FLAG_NOREPLY 0x0002 /* Send no reply to this */
92 #define SILC_MESSAGE_FLAG_ACTION 0x0004 /* Action message */
93 #define SILC_MESSAGE_FLAG_NOTICE 0x0008 /* Notice message */
94 #define SILC_MESSAGE_FLAG_REQUEST 0x0010 /* A request */
95 #define SILC_MESSAGE_FLAG_SIGNED 0x0020 /* Message is signed */
96 #define SILC_MESSAGE_FLAG_REPLY 0x0040 /* A reply */
97 #define SILC_MESSAGE_FLAG_DATA 0x0080 /* MIME object */
98 #define SILC_MESSAGE_FLAG_UTF8 0x0100 /* UTF-8 string */
99 #define SILC_MESSAGE_FLAG_ACK 0x0200 /* ACK messages */
100 #define SILC_MESSAGE_FLAG_RESERVED 0x0400 /* to 0x1000 */
101 #define SILC_MESSAGE_FLAG_PRIVATE 0x2000 /* to 0x8000 */
104 /****f* silccore/SilcMessageAPI/silc_message_payload_decrypt
108 * bool silc_message_payload_decrypt(unsigned char *data,
110 * bool private_message,
118 * Decrypt Message Payload indicated by `data'. If the payload is
119 * channel message then `private_message' is FALSE, and if it is
120 * private message it is TRUE. If the private message key is static
121 * (pre-shared key) then protocol dictates that the IV is present
122 * and `static_key' must be set to TRUE. If the key is not static
123 * (Key Agreement was done for the key) then it MUST be FALSE. For
124 * channel messages the `static_key' is ignored.
126 * This is usually used by the Message Payload interface itself but can
127 * be called by the appliation if separate decryption process is required.
128 * For example server might need to call this directly in some
129 * circumstances. The `cipher' is used to decrypt the payload. If
130 * `check_mac' is FALSE then MAC is not verified.
133 bool silc_message_payload_decrypt(unsigned char *data,
135 bool private_message,
141 /****f* silccore/SilcMessageAPI/silc_message_payload_parse
146 * silc_message_payload_parse(unsigned char *payload,
147 * SilcUInt32 payload_len,
148 * bool private_message,
155 * Parses Message Payload returning new payload structure. This also
156 * decrypts the payload and checks the MAC. If the payload is
157 * channel message then `private_message' is FALSE, and if it is
158 * private message it is TRUE. If the private message key is static
159 * (pre-shared key) then protocol dictates that the IV is present
160 * and `static_key' must be set to TRUE. If the key is not static
161 * (Key Agreement was done for the key) then it MUST be FALSE. For
162 * channel messages the `static_key' is ignored.
164 * If the `hmac' is no provided then the MAC of the channel message is
165 * not verified. If the message is private message and `cipher' is NULL
166 * then this assumes that the packet was decrypted with session keys
167 * (no private message key) and this merely decodes the payload.
171 silc_message_payload_parse(unsigned char *payload,
172 SilcUInt32 payload_len,
173 bool private_message,
178 /****f* silccore/SilcMessageAPI/silc_message_payload_encrypt
182 * bool silc_message_payload_encrypt(unsigned char *data,
183 * SilcUInt32 data_len,
184 * SilcUInt32 true_len,
192 * This function is used to encrypt the Messsage Payload which is
193 * the `data' and `data_len'. The `data_len' is the data length which
194 * is used to create MAC out of. The `data' MUST have additional space
195 * after `true_len' bytes for the MAC which is appended to the data.
197 * This is usually used by the Message Payload interface itself but can
198 * be called by the appliation if separate encryption process is required.
199 * For example server might need to call this directly in some
200 * circumstances. The `cipher' is used to encrypt the payload and `hmac'
201 * to compute the MAC for the payload.
204 bool silc_message_payload_encrypt(unsigned char *data,
212 /****f* silccore/SilcMessageAPI/silc_message_payload_encode
216 * SilcBuffer silc_message_payload_encode(SilcMessageFlags flags,
217 * const unsigned char *data,
218 * SilcUInt32 data_len,
220 * bool private_message,
224 * SilcPublicKey public_key,
225 * SilcPrivateKey private_key,
230 * Encodes a Message Payload into a buffer and returns it. This is
231 * used to encode channel messages and private messages into a packet.
232 * If `private_message' is FALSE then this encodes channel message, if
233 * it is TRUE this encodes private message. If `private_message' is
234 * TRUE then `generate_iv' MUST be FALSE if the private message key
235 * `cipher' is not static key (pre-shared key). If it is static key
236 * then protocol dictates that IV must be present in the Message Payload
237 * and `generate_iv' must be TRUE. The caller must know whether the key
238 * is static or not for private messages. If the key was generated with
239 * Key Agreement protocol then `generate_iv' is always FALSE. For
240 * channel messages `generate_iv' is always set to TRUE value.
242 * The `cipher' is the cipher used to encrypt the message and `hmac'
243 * is used to compute the MAC for the payload. If encoding private
244 * message that will be encrypted with session keys (no private message
245 * key) then `cipher' and `hmac' is NULL and this merely encodes the
246 * payload buffer, and the caller must encrypt the packet later.
247 * If `rng' is NULL then global RNG is used, if non-NULL then the
248 * `rng' is used (for IV and padding generation).
250 * The `public_key', `private_key' and `hash' are provided only if the
251 * flags includes SILC_MESSAGE_FLAG_SIGNED, in which case the message
252 * will be digitally signed. If `public_key' is non-NULL then it will
253 * be included in the message. The `private_message' and `hash' MUST
254 * be provided. The `hash' SHOULD be SHA1.
257 SilcBuffer silc_message_payload_encode(SilcMessageFlags flags,
258 const unsigned char *data,
261 bool private_message,
265 SilcPublicKey public_key,
266 SilcPrivateKey private_key,
269 /****f* silccore/SilcMessageAPI/silc_message_payload_free
273 * void silc_message_payload_free(SilcMessagePayload payload);
277 * Free's Message Payload and all data in it.
280 void silc_message_payload_free(SilcMessagePayload payload);
282 /****f* silccore/SilcMessageAPI/silc_message_get_flags
286 * SilcMessageFlags silc_message_get_flags(SilcMessagePayload payload);
290 * Returns the message flags from the payload.
293 SilcMessageFlags silc_message_get_flags(SilcMessagePayload payload);
295 /****f* silccore/SilcMessageAPI/silc_message_get_data
300 * silc_message_get_data(SilcMessagePayload payload,
301 * SilcUInt32 *data_len);
305 * Return the data in the payload, that is, the actual message data.
306 * The caller must not free it.
309 unsigned char *silc_message_get_data(SilcMessagePayload payload,
310 SilcUInt32 *data_len);
312 /****f* silccore/SilcMessageAPI/silc_message_get_mac
317 * silc_message_get_mac(SilcMessagePayload payload);
321 * Return the MAC of the payload. The caller must already know the
322 * length of the MAC. The caller must not free the MAC.
325 unsigned char *silc_message_get_mac(SilcMessagePayload payload);
327 /****f* silccore/SilcMessageAPI/silc_message_get_iv
332 * silc_message_get_iv(SilcMessagePayload payload);
336 * Return the IV of the payload. The caller must already know the
337 * length of the IV. The caller must not free the IV.
340 unsigned char *silc_message_get_iv(SilcMessagePayload payload);
342 /****f* silccore/SilcMessageAPI/silc_message_get_signature
346 * const SilcMessageSignedPayload
347 * silc_message_get_signature(SilcMessagePayload payload);
351 * Returns the pointer to the signature of the message if the
352 * SILC_MESSAGE_FLAG_SIGNED was set. If the flag is set and this
353 * function returns NULL then error had occurred and the signature
354 * could not be retrieved from the message.
356 * The caller SHOULD verify the signature by calling the
357 * silc_message_signed_verify function.
360 const SilcMessageSignedPayload
361 silc_message_get_signature(SilcMessagePayload payload);
363 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_parse
367 * SilcMessageSignedPayload
368 * silc_message_signed_payload_parse(const unsigned char *data,
369 * SilcUInt32 data_len);
373 * Parses the SilcMessageSignedPayload Payload from the `data' of
374 * length of `data_len' bytes. The `data' must be payload without
375 * the actual message payload. Returns the parsed payload or NULL
376 * on error. Caller must free the returned payload. Application
377 * usually does not need to call this since the function
378 * silc_message_payload_parse calls this automatically for signed
382 SilcMessageSignedPayload
383 silc_message_signed_payload_parse(const unsigned char *data,
384 SilcUInt32 data_len);
386 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_encode
391 * silc_message_signed_payload_encode(const unsigned char *message_payload,
392 * SilcUInt32 message_payload_len,
393 * SilcPublicKey public_key,
394 * SilcPrivateKey private_key,
399 * Encodes the SilcMessageSignedPayload Payload and computes the
400 * digital signature. The `message_payload' is the message data that
401 * is used in the signature computation. The encoding of the buffer
402 * is specified in the SILC protocol. If `public_key' is provided
403 * then the public key included in the payload. The `private_key'
404 * is used to produce the signature. This function returns the encoded
405 * payload with the signature or NULL on error. Caller must free the
406 * returned buffer. The `hash' SHOULD be SHA-1 hash function.
408 * Application usually does not need to call this since the function
409 * silc_message_payload_encode calls this automatically if the caller
410 * wants to sign the message.
414 silc_message_signed_payload_encode(const unsigned char *message_payload,
415 SilcUInt32 message_payload_len,
416 SilcPublicKey public_key,
417 SilcPrivateKey private_key,
420 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_free
424 * void silc_message_signed_payload_free(SilcMessageSignedPayload sig);
428 * Frees the SilcMessageSignedPayload Payload.
431 void silc_message_signed_payload_free(SilcMessageSignedPayload sig);
433 /****f* silccore/SilcMessageAPI/silc_message_signed_verify
437 * int silc_message_signed_verify(SilcMessageSignedPayload sig,
438 * SilcMessagePayload message,
439 * SilcPublicKey remote_public_key,
444 * This routine can be used to verify the signature found in
445 * SilcMessageSignedPayload Payload. This returns SILC_AUTH_OK if the
446 * signature verification was successful.
449 int silc_message_signed_verify(SilcMessageSignedPayload sig,
450 SilcMessagePayload message,
451 SilcPublicKey remote_public_key,
454 /****f* silccore/SilcMessageAPI/silc_message_signed_get_public_key
459 * silc_message_signed_get_public_key(SilcMessageSignedPayload sig,
460 * unsigned char **pk_data,
461 * SilcUInt32 *pk_data_len);
465 * Returns the decoded SilcPublicKey from the SilcMessageSignedPayload
466 * Payload or NULL if it does not include public key. The caller must
467 * free the returned public key pointer. This also returns the raw
468 * public key (before decoding) into `pk_data' and `pk_data_len' if
469 * they are provided. The caller must not free these pointers.
473 silc_message_signed_get_public_key(SilcMessageSignedPayload sig,
474 unsigned char **pk_data,
475 SilcUInt32 *pk_data_len);
477 #endif /* SILCMESSAGE_H */