aboutsummaryrefslogtreecommitdiffstats
path: root/include/olm/olm.h
blob: 838d8178d3a6d178c983c62f7151fbc8025eb4cb (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
/* Copyright 2015, 2016 OpenMarket Ltd
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef OLM_H_
#define OLM_H_

#include <stddef.h>
#include <stdint.h>

#include "olm/inbound_group_session.h"
#include "olm/outbound_group_session.h"

#ifdef __cplusplus
extern "C" {
#endif

static const size_t OLM_MESSAGE_TYPE_PRE_KEY = 0;
static const size_t OLM_MESSAGE_TYPE_MESSAGE = 1;

typedef struct OlmAccount OlmAccount;
typedef struct OlmSession OlmSession;
typedef struct OlmUtility OlmUtility;

/** Get the version number of the library.
 * Arguments will be updated if non-null.
 */
void olm_get_library_version(uint8_t *major, uint8_t *minor, uint8_t *patch);

/** The size of an account object in bytes */
size_t olm_account_size(void);

/** The size of a session object in bytes */
size_t olm_session_size(void);

/** The size of a utility object in bytes */
size_t olm_utility_size(void);

/** Initialise an account object using the supplied memory
 *  The supplied memory must be at least olm_account_size() bytes */
OlmAccount * olm_account(
    void * memory
);

/** Initialise a session object using the supplied memory
 *  The supplied memory must be at least olm_session_size() bytes */
OlmSession * olm_session(
    void * memory
);

/** Initialise a utility object using the supplied memory
 *  The supplied memory must be at least olm_utility_size() bytes */
OlmUtility * olm_utility(
    void * memory
);

/** The value that olm will return from a function if there was an error */
size_t olm_error(void);

/** A null terminated string describing the most recent error to happen to an
 * account */
const char * olm_account_last_error(
    OlmAccount * account
);

/** A null terminated string describing the most recent error to happen to a
 * session */
const char * olm_session_last_error(
    OlmSession * session
);

/** A null terminated string describing the most recent error to happen to a
 * utility */
const char * olm_utility_last_error(
    OlmUtility * utility
);

/** Clears the memory used to back this account */
size_t olm_clear_account(
    OlmAccount * account
);

/** Clears the memory used to back this session */
size_t olm_clear_session(
    OlmSession * session
);

/** Clears the memory used to back this utility */
size_t olm_clear_utility(
    OlmUtility * utility
);

/** Returns the number of bytes needed to store an account */
size_t olm_pickle_account_length(
    OlmAccount * account
);

/** Returns the number of bytes needed to store a session */
size_t olm_pickle_session_length(
    OlmSession * session
);

/** Stores an account as a base64 string. Encrypts the account using the
 * supplied key. Returns the length of the pickled account on success.
 * Returns olm_error() on failure. If the pickle output buffer
 * is smaller than olm_pickle_account_length() then
 * olm_account_last_error() will be "OUTPUT_BUFFER_TOO_SMALL" */
size_t olm_pickle_account(
    OlmAccount * account,
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
);

/** Stores a session as a base64 string. Encrypts the session using the
 * supplied key. Returns the length of the pickled session on success.
 * Returns olm_error() on failure. If the pickle output buffer
 * is smaller than olm_pickle_session_length() then
 * olm_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL" */
size_t olm_pickle_session(
    OlmSession * session,
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
);

/** Loads an account from a pickled base64 string. Decrypts the account using
 * the supplied key. Returns olm_error() on failure. If the key doesn't
 * match the one used to encrypt the account then olm_account_last_error()
 * will be "BAD_ACCOUNT_KEY". If the base64 couldn't be decoded then
 * olm_account_last_error() will be "INVALID_BASE64". The input pickled
 * buffer is destroyed */
size_t olm_unpickle_account(
    OlmAccount * account,
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
);

/** Loads a session from a pickled base64 string. Decrypts the session using
 * the supplied key. Returns olm_error() on failure. If the key doesn't
 * match the one used to encrypt the account then olm_session_last_error()
 * will be "BAD_ACCOUNT_KEY". If the base64 couldn't be decoded then
 * olm_session_last_error() will be "INVALID_BASE64". The input pickled
 * buffer is destroyed */
size_t olm_unpickle_session(
    OlmSession * session,
    void const * key, size_t key_length,
    void * pickled, size_t pickled_length
);

/** The number of random bytes needed to create an account.*/
size_t olm_create_account_random_length(
    OlmAccount * account
);

/** Creates a new account. Returns olm_error() on failure. If weren't
 * enough random bytes then olm_account_last_error() will be
 * "NOT_ENOUGH_RANDOM" */
size_t olm_create_account(
    OlmAccount * account,
    void * random, size_t random_length
);

/** The size of the output buffer needed to hold the identity keys */
size_t olm_account_identity_keys_length(
    OlmAccount * account
);

/** Writes the public parts of the identity keys for the account into the
 * identity_keys output buffer. Returns olm_error() on failure. If the
 * identity_keys buffer was too small then olm_account_last_error() will be
 * "OUTPUT_BUFFER_TOO_SMALL". */
size_t olm_account_identity_keys(
    OlmAccount * account,
    void * identity_keys, size_t identity_key_length
);


/** The length of an ed25519 signature encoded as base64. */
size_t olm_account_signature_length(
    OlmAccount * account
);

/** Signs a message with the ed25519 key for this account. Returns olm_error()
 * on failure. If the signature buffer was too small then
 * olm_account_last_error() will be "OUTPUT_BUFFER_TOO_SMALL" */
size_t olm_account_sign(
    OlmAccount * account,
    void const * message, size_t message_length,
    void * signature, size_t signature_length
);

/** The size of the output buffer needed to hold the one time keys */
size_t olm_account_one_time_keys_length(
    OlmAccount * account
);

/** Writes the public parts of the unpublished one time keys for the account
 * into the one_time_keys output buffer.
 * <p>
 * The returned data is a JSON-formatted object with the single property
 * <tt>curve25519</tt>, which is itself an object mapping key id to
 * base64-encoded Curve25519 key. For example:
 * <pre>
 * {
 *     curve25519: {
 *         "AAAAAA": "wo76WcYtb0Vk/pBOdmduiGJ0wIEjW4IBMbbQn7aSnTo",
 *         "AAAAAB": "LRvjo46L1X2vx69sS9QNFD29HWulxrmW11Up5AfAjgU"
 *     }
 * }
 * </pre>
 * Returns olm_error() on failure.
 * <p>
 * If the one_time_keys buffer was too small then olm_account_last_error()
 * will be "OUTPUT_BUFFER_TOO_SMALL". */
size_t olm_account_one_time_keys(
    OlmAccount * account,
    void * one_time_keys, size_t one_time_keys_length
);

/** Marks the current set of one time keys as being published. */
size_t olm_account_mark_keys_as_published(
    OlmAccount * account
);

/** The largest number of one time keys this account can store. */
size_t olm_account_max_number_of_one_time_keys(
    OlmAccount * account
);

/** The number of random bytes needed to generate a given number of new one
 * time keys. */
size_t olm_account_generate_one_time_keys_random_length(
    OlmAccount * account,
    size_t number_of_keys
);

/** Generates a number of new one time keys. If the total number of keys stored
 * by this account exceeds max_number_of_one_time_keys() then the old keys are
 * discarded. Returns olm_error() on error. If the number of random bytes is
 * too small then olm_account_last_error() will be "NOT_ENOUGH_RANDOM". */
size_t olm_account_generate_one_time_keys(
    OlmAccount * account,
    size_t number_of_keys,
    void * random, size_t random_length
);

/** The number of random bytes needed to create an outbound session */
size_t olm_create_outbound_session_random_length(
    OlmSession * session
);

/** Creates a new out-bound session for sending messages to a given identity_key
 * and one_time_key. Returns olm_error() on failure. If the keys couldn't be
 * decoded as base64 then olm_session_last_error() will be "INVALID_BASE64"
 * If there weren't enough random bytes then olm_session_last_error() will
 * be "NOT_ENOUGH_RANDOM". */
size_t olm_create_outbound_session(
    OlmSession * session,
    OlmAccount * account,
    void const * their_identity_key, size_t their_identity_key_length,
    void const * their_one_time_key, size_t their_one_time_key_length,
    void * random, size_t random_length
);

/** Create a new in-bound session for sending/receiving messages from an
 * incoming PRE_KEY message. Returns olm_error() on failure. If the base64
 * couldn't be decoded then olm_session_last_error will be "INVALID_BASE64".
 * If the message was for an unsupported protocol version then
 * olm_session_last_error() will be "BAD_MESSAGE_VERSION". If the message
 * couldn't be decoded then then olm_session_last_error() will be
 * "BAD_MESSAGE_FORMAT". If the message refers to an unknown one time
 * key then olm_session_last_error() will be "BAD_MESSAGE_KEY_ID". */
size_t olm_create_inbound_session(
    OlmSession * session,
    OlmAccount * account,
    void * one_time_key_message, size_t message_length
);

/** Create a new in-bound session for sending/receiving messages from an
 * incoming PRE_KEY message. Returns olm_error() on failure. If the base64
 * couldn't be decoded then olm_session_last_error will be "INVALID_BASE64".
 * If the message was for an unsupported protocol version then
 * olm_session_last_error() will be "BAD_MESSAGE_VERSION". If the message
 * couldn't be decoded then then olm_session_last_error() will be
 * "BAD_MESSAGE_FORMAT". If the message refers to an unknown one time
 * key then olm_session_last_error() will be "BAD_MESSAGE_KEY_ID". */
size_t olm_create_inbound_session_from(
    OlmSession * session,
    OlmAccount * account,
    void const * their_identity_key, size_t their_identity_key_length,
    void * one_time_key_message, size_t message_length
);

/** The length of the buffer needed to return the id for this session. */
size_t olm_session_id_length(
    OlmSession * session
);

/** An identifier for this session. Will be the same for both ends of the
 * conversation. If the id buffer is too small then olm_session_last_error()
 * will be "OUTPUT_BUFFER_TOO_SMALL". */
size_t olm_session_id(
    OlmSession * session,
    void * id, size_t id_length
);

int olm_session_has_received_message(
    OlmSession *session
);

/** Checks if the PRE_KEY message is for this in-bound session. This can happen
 * if multiple messages are sent to this account before this account sends a
 * message in reply. Returns 1 if the session matches. Returns 0 if the session
 * does not match. Returns olm_error() on failure. If the base64
 * couldn't be decoded then olm_session_last_error will be "INVALID_BASE64".
 * If the message was for an unsupported protocol version then
 * olm_session_last_error() will be "BAD_MESSAGE_VERSION". If the message
 * couldn't be decoded then then olm_session_last_error() will be
 * "BAD_MESSAGE_FORMAT". */
size_t olm_matches_inbound_session(
    OlmSession * session,
    void * one_time_key_message, size_t message_length
);

/** Checks if the PRE_KEY message is for this in-bound session. This can happen
 * if multiple messages are sent to this account before this account sends a
 * message in reply. Returns 1 if the session matches. Returns 0 if the session
 * does not match. Returns olm_error() on failure. If the base64
 * couldn't be decoded then olm_session_last_error will be "INVALID_BASE64".
 * If the message was for an unsupported protocol version then
 * olm_session_last_error() will be "BAD_MESSAGE_VERSION". If the message
 * couldn't be decoded then then olm_session_last_error() will be
 * "BAD_MESSAGE_FORMAT". */
size_t olm_matches_inbound_session_from(
    OlmSession * session,
    void const * their_identity_key, size_t their_identity_key_length,
    void * one_time_key_message, size_t message_length
);

/** Removes the one time keys that the session used from the account. Returns
 * olm_error() on failure. If the account doesn't have any matching one time
 * keys then olm_account_last_error() will be "BAD_MESSAGE_KEY_ID". */
size_t olm_remove_one_time_keys(
    OlmAccount * account,
    OlmSession * session
);

/** The type of the next message that olm_encrypt() will return. Returns
 * OLM_MESSAGE_TYPE_PRE_KEY if the message will be a PRE_KEY message.
 * Returns OLM_MESSAGE_TYPE_MESSAGE if the message will be a normal message.
 * Returns olm_error on failure. */
size_t olm_encrypt_message_type(
    OlmSession * session
);

/** The number of random bytes needed to encrypt the next message. */
size_t olm_encrypt_random_length(
    OlmSession * session
);

/** The size of the next message in bytes for the given number of plain-text
 * bytes. */
size_t olm_encrypt_message_length(
    OlmSession * session,
    size_t plaintext_length
);

/** Encrypts a message using the session. Returns the length of the message in
 * bytes on success. Writes the message as base64 into the message buffer.
 * Returns olm_error() on failure. If the message buffer is too small then
 * olm_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL". If there
 * weren't enough random bytes then olm_session_last_error() will be
 * "NOT_ENOUGH_RANDOM". */
size_t olm_encrypt(
    OlmSession * session,
    void const * plaintext, size_t plaintext_length,
    void * random, size_t random_length,
    void * message, size_t message_length
);

/** The maximum number of bytes of plain-text a given message could decode to.
 * The actual size could be different due to padding. The input message buffer
 * is destroyed. Returns olm_error() on failure. If the message base64
 * couldn't be decoded then olm_session_last_error() will be
 * "INVALID_BASE64". If the message is for an unsupported version of the
 * protocol then olm_session_last_error() will be "BAD_MESSAGE_VERSION".
 * If the message couldn't be decoded then olm_session_last_error() will be
 * "BAD_MESSAGE_FORMAT". */
size_t olm_decrypt_max_plaintext_length(
    OlmSession * session,
    size_t message_type,
    void * message, size_t message_length
);

/** Decrypts a message using the session. The input message buffer is destroyed.
 * Returns the length of the plain-text on success. Returns olm_error() on
 * failure. If the plain-text buffer is smaller than
 * olm_decrypt_max_plaintext_length() then olm_session_last_error()
 * will be "OUTPUT_BUFFER_TOO_SMALL". If the base64 couldn't be decoded then
 * olm_session_last_error() will be "INVALID_BASE64". If the message is for
 * an unsupported version of the protocol then olm_session_last_error() will
 *  be "BAD_MESSAGE_VERSION". If the message couldn't be decoded then
 *  olm_session_last_error() will be BAD_MESSAGE_FORMAT".
 *  If the MAC on the message was invalid then olm_session_last_error() will
 *  be "BAD_MESSAGE_MAC". */
size_t olm_decrypt(
    OlmSession * session,
    size_t message_type,
    void * message, size_t message_length,
    void * plaintext, size_t max_plaintext_length
);

/** The length of the buffer needed to hold the SHA-256 hash. */
size_t olm_sha256_length(
   OlmUtility * utility
);

/** Calculates the SHA-256 hash of the input and encodes it as base64. If the
 * output buffer is smaller than olm_sha256_length() then
 * olm_session_last_error() will be "OUTPUT_BUFFER_TOO_SMALL". */
size_t olm_sha256(
    OlmUtility * utility,
    void const * input, size_t input_length,
    void * output, size_t output_length
);

/** Verify an ed25519 signature. If the key was too small then
 * olm_session_last_error will be "INVALID_BASE64". If the signature was invalid
 * then olm_session_last_error() will be "BAD_MESSAGE_MAC". */
size_t olm_ed25519_verify(
    OlmUtility * utility,
    void const * key, size_t key_length,
    void const * message, size_t message_length,
    void * signature, size_t signature_length
);

#ifdef __cplusplus
}
#endif

#endif /* OLM_HH_ */