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_RESERVED 0x0200 /* to 0x0800 */
100 #define SILC_MESSAGE_FLAG_PRIVATE 0x1000 /* to 0x8000 */
103 /****f* silccore/SilcMessageAPI/silc_message_payload_decrypt
107 * bool silc_message_payload_decrypt(unsigned char *data,
109 * bool private_message,
117 * Decrypt Message Payload indicated by `data'. If the payload is
118 * channel message then `private_message' is FALSE, and if it is
119 * private message it is TRUE. If the private message key is static
120 * (pre-shared key) then protocol dictates that the IV is present
121 * and `static_key' must be set to TRUE. If the key is not static
122 * (Key Agreement was done for the key) then it MUST be FALSE. For
123 * channel messages the `static_key' is ignored.
125 * This is usually used by the Message Payload interface itself but can
126 * be called by the appliation if separate decryption process is required.
127 * For example server might need to call this directly in some
128 * circumstances. The `cipher' is used to decrypt the payload. If
129 * `check_mac' is FALSE then MAC is not verified.
132 bool silc_message_payload_decrypt(unsigned char *data,
134 bool private_message,
140 /****f* silccore/SilcMessageAPI/silc_message_payload_parse
145 * silc_message_payload_parse(unsigned char *payload,
146 * SilcUInt32 payload_len,
147 * bool private_message,
154 * Parses Message Payload returning new payload structure. This also
155 * decrypts the payload and checks the MAC. If the payload is
156 * channel message then `private_message' is FALSE, and if it is
157 * private message it is TRUE. If the private message key is static
158 * (pre-shared key) then protocol dictates that the IV is present
159 * and `static_key' must be set to TRUE. If the key is not static
160 * (Key Agreement was done for the key) then it MUST be FALSE. For
161 * channel messages the `static_key' is ignored.
163 * If the `hmac' is no provided then the MAC of the channel message is
164 * not verified. If the message is private message and `cipher' is NULL
165 * then this assumes that the packet was decrypted with session keys
166 * (no private message key) and this merely decodes the payload.
170 silc_message_payload_parse(unsigned char *payload,
171 SilcUInt32 payload_len,
172 bool private_message,
177 /****f* silccore/SilcMessageAPI/silc_message_payload_encrypt
181 * bool silc_message_payload_encrypt(unsigned char *data,
182 * SilcUInt32 data_len,
183 * SilcUInt32 true_len,
191 * This function is used to encrypt the Messsage Payload which is
192 * the `data' and `data_len'. The `data_len' is the data length which
193 * is used to create MAC out of. The `data' MUST have additional space
194 * after `true_len' bytes for the MAC which is appended to the data.
196 * This is usually used by the Message Payload interface itself but can
197 * be called by the appliation if separate encryption process is required.
198 * For example server might need to call this directly in some
199 * circumstances. The `cipher' is used to encrypt the payload and `hmac'
200 * to compute the MAC for the payload.
203 bool silc_message_payload_encrypt(unsigned char *data,
211 /****f* silccore/SilcMessageAPI/silc_message_payload_encode
215 * SilcBuffer silc_message_payload_encode(SilcMessageFlags flags,
216 * const unsigned char *data,
217 * SilcUInt32 data_len,
219 * bool private_message,
223 * SilcPublicKey public_key,
224 * SilcPrivateKey private_key,
229 * Encodes a Message Payload into a buffer and returns it. This is
230 * used to encode channel messages and private messages into a packet.
231 * If `private_message' is FALSE then this encodes channel message, if
232 * it is TRUE this encodes private message. If `private_message' is
233 * TRUE then `generate_iv' MUST be FALSE if the private message key
234 * `cipher' is not static key (pre-shared key). If it is static key
235 * then protocol dictates that IV must be present in the Message Payload
236 * and `generate_iv' must be TRUE. The caller must know whether the key
237 * is static or not for private messages. If the key was generated with
238 * Key Agreement protocol then `generate_iv' is always FALSE. For
239 * channel messages `generate_iv' is always set to TRUE value.
241 * The `cipher' is the cipher used to encrypt the message and `hmac'
242 * is used to compute the MAC for the payload. If encoding private
243 * message that will be encrypted with session keys (no private message
244 * key) then `cipher' and `hmac' is NULL and this merely encodes the
245 * payload buffer, and the caller must encrypt the packet later.
246 * If `rng' is NULL then global RNG is used, if non-NULL then the
247 * `rng' is used (for IV and padding generation).
249 * The `public_key', `private_key' and `hash' are provided only if the
250 * flags includes SILC_MESSAGE_FLAG_SIGNED, in which case the message
251 * will be digitally signed. If `public_key' is non-NULL then it will
252 * be included in the message. The `private_message' and `hash' MUST
253 * be provided. The `hash' SHOULD be SHA1.
256 SilcBuffer silc_message_payload_encode(SilcMessageFlags flags,
257 const unsigned char *data,
260 bool private_message,
264 SilcPublicKey public_key,
265 SilcPrivateKey private_key,
268 /****f* silccore/SilcMessageAPI/silc_message_payload_free
272 * void silc_message_payload_free(SilcMessagePayload payload);
276 * Free's Message Payload and all data in it.
279 void silc_message_payload_free(SilcMessagePayload payload);
281 /****f* silccore/SilcMessageAPI/silc_message_get_flags
285 * SilcMessageFlags silc_message_get_flags(SilcMessagePayload payload);
289 * Returns the message flags from the payload.
292 SilcMessageFlags silc_message_get_flags(SilcMessagePayload payload);
294 /****f* silccore/SilcMessageAPI/silc_message_get_data
299 * silc_message_get_data(SilcMessagePayload payload,
300 * SilcUInt32 *data_len);
304 * Return the data in the payload, that is, the actual message data.
305 * The caller must not free it.
308 unsigned char *silc_message_get_data(SilcMessagePayload payload,
309 SilcUInt32 *data_len);
311 /****f* silccore/SilcMessageAPI/silc_message_get_mac
316 * silc_message_get_mac(SilcMessagePayload payload);
320 * Return the MAC of the payload. The caller must already know the
321 * length of the MAC. The caller must not free the MAC.
324 unsigned char *silc_message_get_mac(SilcMessagePayload payload);
326 /****f* silccore/SilcMessageAPI/silc_message_get_iv
331 * silc_message_get_iv(SilcMessagePayload payload);
335 * Return the IV of the payload. The caller must already know the
336 * length of the IV. The caller must not free the IV.
339 unsigned char *silc_message_get_iv(SilcMessagePayload payload);
341 /****f* silccore/SilcMessageAPI/silc_message_get_signature
345 * const SilcMessageSignedPayload
346 * silc_message_get_signature(SilcMessagePayload payload);
350 * Returns the pointer to the signature of the message if the
351 * SILC_MESSAGE_FLAG_SIGNED was set. If the flag is set and this
352 * function returns NULL then error had occurred and the signature
353 * could not be retrieved from the message.
355 * The caller SHOULD verify the signature by calling the
356 * silc_message_signed_verify function.
359 const SilcMessageSignedPayload
360 silc_message_get_signature(SilcMessagePayload payload);
362 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_parse
366 * SilcMessageSignedPayload
367 * silc_message_signed_payload_parse(const unsigned char *data,
368 * SilcUInt32 data_len);
372 * Parses the SilcMessageSignedPayload Payload from the `data' of
373 * length of `data_len' bytes. The `data' must be payload without
374 * the actual message payload. Returns the parsed payload or NULL
375 * on error. Caller must free the returned payload. Application
376 * usually does not need to call this since the function
377 * silc_message_payload_parse calls this automatically for signed
381 SilcMessageSignedPayload
382 silc_message_signed_payload_parse(const unsigned char *data,
383 SilcUInt32 data_len);
385 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_encode
390 * silc_message_signed_payload_encode(const unsigned char *message_payload,
391 * SilcUInt32 message_payload_len,
392 * SilcPublicKey public_key,
393 * SilcPrivateKey private_key,
398 * Encodes the SilcMessageSignedPayload Payload and computes the
399 * digital signature. The `message_payload' is the message data that
400 * is used in the signature computation. The encoding of the buffer
401 * is specified in the SILC protocol. If `public_key' is provided
402 * then the public key included in the payload. The `private_key'
403 * is used to produce the signature. This function returns the encoded
404 * payload with the signature or NULL on error. Caller must free the
405 * returned buffer. The `hash' SHOULD be SHA-1 hash function.
407 * Application usually does not need to call this since the function
408 * silc_message_payload_encode calls this automatically if the caller
409 * wants to sign the message.
413 silc_message_signed_payload_encode(const unsigned char *message_payload,
414 SilcUInt32 message_payload_len,
415 SilcPublicKey public_key,
416 SilcPrivateKey private_key,
419 /****f* silccore/SilcMessageAPI/silc_message_signed_payload_free
423 * void silc_message_signed_payload_free(SilcMessageSignedPayload sig);
427 * Frees the SilcMessageSignedPayload Payload.
430 void silc_message_signed_payload_free(SilcMessageSignedPayload sig);
432 /****f* silccore/SilcMessageAPI/silc_message_signed_verify
436 * int silc_message_signed_verify(SilcMessageSignedPayload sig,
437 * SilcMessagePayload message,
438 * SilcPublicKey remote_public_key,
443 * This routine can be used to verify the signature found in
444 * SilcMessageSignedPayload Payload. This returns SILC_AUTH_OK if the
445 * signature verification was successful.
448 int silc_message_signed_verify(SilcMessageSignedPayload sig,
449 SilcMessagePayload message,
450 SilcPublicKey remote_public_key,
453 /****f* silccore/SilcMessageAPI/silc_message_signed_get_public_key
458 * silc_message_signed_get_public_key(SilcMessageSignedPayload sig);
462 * Returns the decoded SilcPublicKey from the SilcMessageSignedPayload
463 * Payload or NULL if it does not include public key. The caller must
464 * free the returned public key pointer. This also returns the raw
465 * public key (before decoding) into `pk_data' and `pk_data_len' if
466 * they are provided. The caller must not free these pointers.
470 silc_message_signed_get_public_key(SilcMessageSignedPayload sig,
471 unsigned char **pk_data,
472 SilcUInt32 *pk_data_len);
474 #endif /* SILCMESSAGE_H */