This file is indexed.

/usr/include/mbedtls/cipher.h is in libmbedtls-dev 2.8.0-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
/**
 * \file cipher.h
 *
 * \brief The generic cipher wrapper.
 *
 * \author Adriaan de Jong <dejong@fox-it.com>
 */
/*
 *  Copyright (C) 2006-2018, Arm Limited (or its affiliates), All Rights Reserved
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  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.
 *
 *  This file is part of Mbed TLS (https://tls.mbed.org)
 */

#ifndef MBEDTLS_CIPHER_H
#define MBEDTLS_CIPHER_H

#if !defined(MBEDTLS_CONFIG_FILE)
#include "config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#include <stddef.h>

#if defined(MBEDTLS_GCM_C) || defined(MBEDTLS_CCM_C)
#define MBEDTLS_CIPHER_MODE_AEAD
#endif

#if defined(MBEDTLS_CIPHER_MODE_CBC)
#define MBEDTLS_CIPHER_MODE_WITH_PADDING
#endif

#if defined(MBEDTLS_ARC4_C)
#define MBEDTLS_CIPHER_MODE_STREAM
#endif

#if ( defined(__ARMCC_VERSION) || defined(_MSC_VER) ) && \
    !defined(inline) && !defined(__cplusplus)
#define inline __inline
#endif

#define MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE  -0x6080  /**< The selected feature is not available. */
#define MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA       -0x6100  /**< Bad input parameters. */
#define MBEDTLS_ERR_CIPHER_ALLOC_FAILED         -0x6180  /**< Failed to allocate memory. */
#define MBEDTLS_ERR_CIPHER_INVALID_PADDING      -0x6200  /**< Input data contains invalid padding and is rejected. */
#define MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED  -0x6280  /**< Decryption of block requires a full block. */
#define MBEDTLS_ERR_CIPHER_AUTH_FAILED          -0x6300  /**< Authentication failed (for AEAD modes). */
#define MBEDTLS_ERR_CIPHER_INVALID_CONTEXT      -0x6380  /**< The context is invalid. For example, because it was freed. */
#define MBEDTLS_ERR_CIPHER_HW_ACCEL_FAILED      -0x6400  /**< Cipher hardware accelerator failed. */

#define MBEDTLS_CIPHER_VARIABLE_IV_LEN     0x01    /**< Cipher accepts IVs of variable length. */
#define MBEDTLS_CIPHER_VARIABLE_KEY_LEN    0x02    /**< Cipher accepts keys of variable length. */

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \brief     An enumeration of supported ciphers.
 *
 * \warning   ARC4 and DES are considered weak ciphers and their use
 *            constitutes a security risk. We recommend considering stronger
 *            ciphers instead.
 */
typedef enum {
    MBEDTLS_CIPHER_ID_NONE = 0,
    MBEDTLS_CIPHER_ID_NULL,
    MBEDTLS_CIPHER_ID_AES,
    MBEDTLS_CIPHER_ID_DES,
    MBEDTLS_CIPHER_ID_3DES,
    MBEDTLS_CIPHER_ID_CAMELLIA,
    MBEDTLS_CIPHER_ID_BLOWFISH,
    MBEDTLS_CIPHER_ID_ARC4,
} mbedtls_cipher_id_t;

/**
 * \brief     An enumeration of supported (cipher, mode) pairs.
 *
 * \warning   ARC4 and DES are considered weak ciphers and their use
 *            constitutes a security risk. We recommend considering stronger
 *            ciphers instead.
 */
typedef enum {
    MBEDTLS_CIPHER_NONE = 0,
    MBEDTLS_CIPHER_NULL,
    MBEDTLS_CIPHER_AES_128_ECB,
    MBEDTLS_CIPHER_AES_192_ECB,
    MBEDTLS_CIPHER_AES_256_ECB,
    MBEDTLS_CIPHER_AES_128_CBC,
    MBEDTLS_CIPHER_AES_192_CBC,
    MBEDTLS_CIPHER_AES_256_CBC,
    MBEDTLS_CIPHER_AES_128_CFB128,
    MBEDTLS_CIPHER_AES_192_CFB128,
    MBEDTLS_CIPHER_AES_256_CFB128,
    MBEDTLS_CIPHER_AES_128_CTR,
    MBEDTLS_CIPHER_AES_192_CTR,
    MBEDTLS_CIPHER_AES_256_CTR,
    MBEDTLS_CIPHER_AES_128_GCM,
    MBEDTLS_CIPHER_AES_192_GCM,
    MBEDTLS_CIPHER_AES_256_GCM,
    MBEDTLS_CIPHER_CAMELLIA_128_ECB,
    MBEDTLS_CIPHER_CAMELLIA_192_ECB,
    MBEDTLS_CIPHER_CAMELLIA_256_ECB,
    MBEDTLS_CIPHER_CAMELLIA_128_CBC,
    MBEDTLS_CIPHER_CAMELLIA_192_CBC,
    MBEDTLS_CIPHER_CAMELLIA_256_CBC,
    MBEDTLS_CIPHER_CAMELLIA_128_CFB128,
    MBEDTLS_CIPHER_CAMELLIA_192_CFB128,
    MBEDTLS_CIPHER_CAMELLIA_256_CFB128,
    MBEDTLS_CIPHER_CAMELLIA_128_CTR,
    MBEDTLS_CIPHER_CAMELLIA_192_CTR,
    MBEDTLS_CIPHER_CAMELLIA_256_CTR,
    MBEDTLS_CIPHER_CAMELLIA_128_GCM,
    MBEDTLS_CIPHER_CAMELLIA_192_GCM,
    MBEDTLS_CIPHER_CAMELLIA_256_GCM,
    MBEDTLS_CIPHER_DES_ECB,
    MBEDTLS_CIPHER_DES_CBC,
    MBEDTLS_CIPHER_DES_EDE_ECB,
    MBEDTLS_CIPHER_DES_EDE_CBC,
    MBEDTLS_CIPHER_DES_EDE3_ECB,
    MBEDTLS_CIPHER_DES_EDE3_CBC,
    MBEDTLS_CIPHER_BLOWFISH_ECB,
    MBEDTLS_CIPHER_BLOWFISH_CBC,
    MBEDTLS_CIPHER_BLOWFISH_CFB64,
    MBEDTLS_CIPHER_BLOWFISH_CTR,
    MBEDTLS_CIPHER_ARC4_128,
    MBEDTLS_CIPHER_AES_128_CCM,
    MBEDTLS_CIPHER_AES_192_CCM,
    MBEDTLS_CIPHER_AES_256_CCM,
    MBEDTLS_CIPHER_CAMELLIA_128_CCM,
    MBEDTLS_CIPHER_CAMELLIA_192_CCM,
    MBEDTLS_CIPHER_CAMELLIA_256_CCM,
} mbedtls_cipher_type_t;

/** Supported cipher modes. */
typedef enum {
    MBEDTLS_MODE_NONE = 0,
    MBEDTLS_MODE_ECB,
    MBEDTLS_MODE_CBC,
    MBEDTLS_MODE_CFB,
    MBEDTLS_MODE_OFB, /* Unused! */
    MBEDTLS_MODE_CTR,
    MBEDTLS_MODE_GCM,
    MBEDTLS_MODE_STREAM,
    MBEDTLS_MODE_CCM,
} mbedtls_cipher_mode_t;

/** Supported cipher padding types. */
typedef enum {
    MBEDTLS_PADDING_PKCS7 = 0,     /**< PKCS7 padding (default).        */
    MBEDTLS_PADDING_ONE_AND_ZEROS, /**< ISO/IEC 7816-4 padding.         */
    MBEDTLS_PADDING_ZEROS_AND_LEN, /**< ANSI X.923 padding.             */
    MBEDTLS_PADDING_ZEROS,         /**< zero padding (not reversible). */
    MBEDTLS_PADDING_NONE,          /**< never pad (full blocks only).   */
} mbedtls_cipher_padding_t;

/** Type of operation. */
typedef enum {
    MBEDTLS_OPERATION_NONE = -1,
    MBEDTLS_DECRYPT = 0,
    MBEDTLS_ENCRYPT,
} mbedtls_operation_t;

enum {
    /** Undefined key length. */
    MBEDTLS_KEY_LENGTH_NONE = 0,
    /** Key length, in bits (including parity), for DES keys. */
    MBEDTLS_KEY_LENGTH_DES  = 64,
    /** Key length in bits, including parity, for DES in two-key EDE. */
    MBEDTLS_KEY_LENGTH_DES_EDE = 128,
    /** Key length in bits, including parity, for DES in three-key EDE. */
    MBEDTLS_KEY_LENGTH_DES_EDE3 = 192,
};

/** Maximum length of any IV, in Bytes. */
#define MBEDTLS_MAX_IV_LENGTH      16
/** Maximum block size of any cipher, in Bytes. */
#define MBEDTLS_MAX_BLOCK_LENGTH   16

/**
 * Base cipher information (opaque struct).
 */
typedef struct mbedtls_cipher_base_t mbedtls_cipher_base_t;

/**
 * CMAC context (opaque struct).
 */
typedef struct mbedtls_cmac_context_t mbedtls_cmac_context_t;

/**
 * Cipher information. Allows calling cipher functions
 * in a generic way.
 */
typedef struct {
    /** Full cipher identifier. For example,
     * MBEDTLS_CIPHER_AES_256_CBC.
     */
    mbedtls_cipher_type_t type;

    /** The cipher mode. For example, MBEDTLS_MODE_CBC. */
    mbedtls_cipher_mode_t mode;

    /** The cipher key length, in bits. This is the
     * default length for variable sized ciphers.
     * Includes parity bits for ciphers like DES.
     */
    unsigned int key_bitlen;

    /** Name of the cipher. */
    const char * name;

    /** IV or nonce size, in Bytes.
     * For ciphers that accept variable IV sizes,
     * this is the recommended size.
     */
    unsigned int iv_size;

    /** Flags to set. For example, if the cipher supports variable IV sizes or variable key sizes. */
    int flags;

    /** The block size, in Bytes. */
    unsigned int block_size;

    /** Struct for base cipher information and functions. */
    const mbedtls_cipher_base_t *base;

} mbedtls_cipher_info_t;

/**
 * Generic cipher context.
 */
typedef struct {
    /** Information about the associated cipher. */
    const mbedtls_cipher_info_t *cipher_info;

    /** Key length to use. */
    int key_bitlen;

    /** Operation that the key of the context has been
     * initialized for.
     */
    mbedtls_operation_t operation;

#if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
    /** Padding functions to use, if relevant for
     * the specific cipher mode.
     */
    void (*add_padding)( unsigned char *output, size_t olen, size_t data_len );
    int (*get_padding)( unsigned char *input, size_t ilen, size_t *data_len );
#endif

    /** Buffer for input that has not been processed yet. */
    unsigned char unprocessed_data[MBEDTLS_MAX_BLOCK_LENGTH];

    /** Number of Bytes that have not been processed yet. */
    size_t unprocessed_len;

    /** Current IV or NONCE_COUNTER for CTR-mode. */
    unsigned char iv[MBEDTLS_MAX_IV_LENGTH];

    /** IV size in Bytes, for ciphers with variable-length IVs. */
    size_t iv_size;

    /** The cipher-specific context. */
    void *cipher_ctx;

#if defined(MBEDTLS_CMAC_C)
    /** CMAC-specific context. */
    mbedtls_cmac_context_t *cmac_ctx;
#endif
} mbedtls_cipher_context_t;

/**
 * \brief This function retrieves the list of ciphers supported by the generic
 * cipher module.
 *
 * \return      A statically-allocated array of ciphers. The last entry
 *              is zero.
 */
const int *mbedtls_cipher_list( void );

/**
 * \brief               This function retrieves the cipher-information
 *                      structure associated with the given cipher name.
 *
 * \param cipher_name   Name of the cipher to search for.
 *
 * \return              The cipher information structure associated with the
 *                      given \p cipher_name, or NULL if not found.
 */
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_string( const char *cipher_name );

/**
 * \brief               This function retrieves the cipher-information
 *                      structure associated with the given cipher type.
 *
 * \param cipher_type   Type of the cipher to search for.
 *
 * \return              The cipher information structure associated with the
 *                      given \p cipher_type, or NULL if not found.
 */
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_type( const mbedtls_cipher_type_t cipher_type );

/**
 * \brief               This function retrieves the cipher-information
 *                      structure associated with the given cipher ID,
 *                      key size and mode.
 *
 * \param cipher_id     The ID of the cipher to search for. For example,
 *                      #MBEDTLS_CIPHER_ID_AES.
 * \param key_bitlen    The length of the key in bits.
 * \param mode          The cipher mode. For example, #MBEDTLS_MODE_CBC.
 *
 * \return              The cipher information structure associated with the
 *                      given \p cipher_id, or NULL if not found.
 */
const mbedtls_cipher_info_t *mbedtls_cipher_info_from_values( const mbedtls_cipher_id_t cipher_id,
                                              int key_bitlen,
                                              const mbedtls_cipher_mode_t mode );

/**
 * \brief               This function initializes a \p cipher_context as NONE.
 */
void mbedtls_cipher_init( mbedtls_cipher_context_t *ctx );

/**
 * \brief               This function frees and clears the cipher-specific
 *                      context of \p ctx. Freeing \p ctx itself remains the
 *                      responsibility of the caller.
 */
void mbedtls_cipher_free( mbedtls_cipher_context_t *ctx );


/**
 * \brief               This function initializes and fills the cipher-context
 *                      structure with the appropriate values. It also clears
 *                      the structure.
 *
 * \param ctx           The context to initialize. May not be NULL.
 * \param cipher_info   The cipher to use.
 *
 * \return              \c 0 on success,
 *                      #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA on parameter failure,
 *                      #MBEDTLS_ERR_CIPHER_ALLOC_FAILED if allocation of the
 *                      cipher-specific context failed.
 *
 * \internal Currently, the function also clears the structure.
 * In future versions, the caller will be required to call
 * mbedtls_cipher_init() on the structure first.
 */
int mbedtls_cipher_setup( mbedtls_cipher_context_t *ctx, const mbedtls_cipher_info_t *cipher_info );

/**
 * \brief        This function returns the block size of the given cipher.
 *
 * \param ctx    The context of the cipher. Must be initialized.
 *
 * \return       The size of the blocks of the cipher, or zero if \p ctx
 *               has not been initialized.
 */
static inline unsigned int mbedtls_cipher_get_block_size( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return 0;

    return ctx->cipher_info->block_size;
}

/**
 * \brief        This function returns the mode of operation for
 *               the cipher. For example, MBEDTLS_MODE_CBC.
 *
 * \param ctx    The context of the cipher. Must be initialized.
 *
 * \return       The mode of operation, or #MBEDTLS_MODE_NONE if
 *               \p ctx has not been initialized.
 */
static inline mbedtls_cipher_mode_t mbedtls_cipher_get_cipher_mode( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return MBEDTLS_MODE_NONE;

    return ctx->cipher_info->mode;
}

/**
 * \brief       This function returns the size of the IV or nonce
 *              of the cipher, in Bytes.
 *
 * \param ctx   The context of the cipher. Must be initialized.
 *
 * \return      <ul><li>If no IV has been set: the recommended IV size.
 *              0 for ciphers not using IV or nonce.</li>
 *              <li>If IV has already been set: the actual size.</li></ul>
 */
static inline int mbedtls_cipher_get_iv_size( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return 0;

    if( ctx->iv_size != 0 )
        return (int) ctx->iv_size;

    return (int) ctx->cipher_info->iv_size;
}

/**
 * \brief               This function returns the type of the given cipher.
 *
 * \param ctx           The context of the cipher. Must be initialized.
 *
 * \return              The type of the cipher, or #MBEDTLS_CIPHER_NONE if
 *                      \p ctx has not been initialized.
 */
static inline mbedtls_cipher_type_t mbedtls_cipher_get_type( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return MBEDTLS_CIPHER_NONE;

    return ctx->cipher_info->type;
}

/**
 * \brief               This function returns the name of the given cipher
 *                      as a string.
 *
 * \param ctx           The context of the cipher. Must be initialized.
 *
 * \return              The name of the cipher, or NULL if \p ctx has not
 *                      been not initialized.
 */
static inline const char *mbedtls_cipher_get_name( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return 0;

    return ctx->cipher_info->name;
}

/**
 * \brief               This function returns the key length of the cipher.
 *
 * \param ctx           The context of the cipher. Must be initialized.
 *
 * \return              The key length of the cipher in bits, or
 *                      #MBEDTLS_KEY_LENGTH_NONE if ctx \p has not been
 *                      initialized.
 */
static inline int mbedtls_cipher_get_key_bitlen( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return MBEDTLS_KEY_LENGTH_NONE;

    return (int) ctx->cipher_info->key_bitlen;
}

/**
 * \brief          This function returns the operation of the given cipher.
 *
 * \param ctx      The context of the cipher. Must be initialized.
 *
 * \return         The type of operation: #MBEDTLS_ENCRYPT or
 *                 #MBEDTLS_DECRYPT, or #MBEDTLS_OPERATION_NONE if \p ctx
 *                 has not been initialized.
 */
static inline mbedtls_operation_t mbedtls_cipher_get_operation( const mbedtls_cipher_context_t *ctx )
{
    if( NULL == ctx || NULL == ctx->cipher_info )
        return MBEDTLS_OPERATION_NONE;

    return ctx->operation;
}

/**
 * \brief               This function sets the key to use with the given context.
 *
 * \param ctx           The generic cipher context. May not be NULL. Must have
 *                      been initialized using mbedtls_cipher_info_from_type()
 *                      or mbedtls_cipher_info_from_string().
 * \param key           The key to use.
 * \param key_bitlen    The key length to use, in bits.
 * \param operation     The operation that the key will be used for:
 *                      #MBEDTLS_ENCRYPT or #MBEDTLS_DECRYPT.
 *
 * \returns             \c 0 on success, #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
 *                      parameter verification fails, or a cipher-specific
 *                      error code.
 */
int mbedtls_cipher_setkey( mbedtls_cipher_context_t *ctx, const unsigned char *key,
                   int key_bitlen, const mbedtls_operation_t operation );

#if defined(MBEDTLS_CIPHER_MODE_WITH_PADDING)
/**
 * \brief               This function sets the padding mode, for cipher modes
 *                      that use padding.
 *
 *                      The default passing mode is PKCS7 padding.
 *
 * \param ctx           The generic cipher context.
 * \param mode          The padding mode.
 *
 * \returns             \c 0 on success, #MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE
 *                      if the selected padding mode is not supported, or
 *                      #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if the cipher mode
 *                      does not support padding.
 */
int mbedtls_cipher_set_padding_mode( mbedtls_cipher_context_t *ctx, mbedtls_cipher_padding_t mode );
#endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */

/**
 * \brief           This function sets the initialization vector (IV)
 *                  or nonce.
 *
 * \param ctx       The generic cipher context.
 * \param iv        The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
 * \param iv_len    The IV length for ciphers with variable-size IV.
 *                  This parameter is discarded by ciphers with fixed-size IV.
 *
 * \returns         \c 0 on success, or #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 *
 * \note            Some ciphers do not use IVs nor nonce. For these
 *                  ciphers, this function has no effect.
 */
int mbedtls_cipher_set_iv( mbedtls_cipher_context_t *ctx,
                   const unsigned char *iv, size_t iv_len );

/**
 * \brief         This function resets the cipher state.
 *
 * \param ctx     The generic cipher context.
 *
 * \returns       \c 0 on success, #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA
 *                if parameter verification fails.
 */
int mbedtls_cipher_reset( mbedtls_cipher_context_t *ctx );

#if defined(MBEDTLS_GCM_C)
/**
 * \brief               This function adds additional data for AEAD ciphers.
 *                      Only supported with GCM. Must be called
 *                      exactly once, after mbedtls_cipher_reset().
 *
 * \param ctx           The generic cipher context.
 * \param ad            The additional data to use.
 * \param ad_len        the Length of \p ad.
 *
 * \return              \c 0 on success, or a specific error code on failure.
 */
int mbedtls_cipher_update_ad( mbedtls_cipher_context_t *ctx,
                      const unsigned char *ad, size_t ad_len );
#endif /* MBEDTLS_GCM_C */

/**
 * \brief               The generic cipher update function. It encrypts or
 *                      decrypts using the given cipher context. Writes as
 *                      many block-sized blocks of data as possible to output.
 *                      Any data that cannot be written immediately is either
 *                      added to the next block, or flushed when
 *                      mbedtls_cipher_finish() is called.
 *                      Exception: For MBEDTLS_MODE_ECB, expects a single block
 *                      in size. For example, 16 Bytes for AES.
 *
 * \param ctx           The generic cipher context.
 * \param input         The buffer holding the input data.
 * \param ilen          The length of the input data.
 * \param output        The buffer for the output data. Must be able to hold at
 *                      least \p ilen + block_size. Must not be the same buffer
 *                      as input.
 * \param olen          The length of the output data, to be updated with the
 *                      actual number of Bytes written.
 *
 * \returns             \c 0 on success, #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
 *                      parameter verification fails,
 *                      #MBEDTLS_ERR_CIPHER_FEATURE_UNAVAILABLE on an
 *                      unsupported mode for a cipher, or a cipher-specific
 *                      error code.
 *
 * \note                If the underlying cipher is GCM, all calls to this
 *                      function, except the last one before
 *                      mbedtls_cipher_finish(). Must have \p ilen as a
 *                      multiple of the block_size.
 */
int mbedtls_cipher_update( mbedtls_cipher_context_t *ctx, const unsigned char *input,
                   size_t ilen, unsigned char *output, size_t *olen );

/**
 * \brief               The generic cipher finalization function. If data still
 *                      needs to be flushed from an incomplete block, the data
 *                      contained in it is padded to the size of
 *                      the last block, and written to the \p output buffer.
 *
 * \param ctx           The generic cipher context.
 * \param output        The buffer to write data to. Needs block_size available.
 * \param olen          The length of the data written to the \p output buffer.
 *
 * \returns             \c 0 on success, #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA if
 *                      parameter verification fails,
 *                      #MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
 *                      expected a full block but was not provided one,
 *                      #MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
 *                      while decrypting, or a cipher-specific error code
 *                      on failure for any other reason.
 */
int mbedtls_cipher_finish( mbedtls_cipher_context_t *ctx,
                   unsigned char *output, size_t *olen );

#if defined(MBEDTLS_GCM_C)
/**
 * \brief               This function writes a tag for AEAD ciphers.
 *                      Only supported with GCM.
 *                      Must be called after mbedtls_cipher_finish().
 *
 * \param ctx           The generic cipher context.
 * \param tag           The buffer to write the tag to.
 * \param tag_len       The length of the tag to write.
 *
 * \return              \c 0 on success, or a specific error code on failure.
 */
int mbedtls_cipher_write_tag( mbedtls_cipher_context_t *ctx,
                      unsigned char *tag, size_t tag_len );

/**
 * \brief               This function checks the tag for AEAD ciphers.
 *                      Only supported with GCM.
 *                      Must be called after mbedtls_cipher_finish().
 *
 * \param ctx           The generic cipher context.
 * \param tag           The buffer holding the tag.
 * \param tag_len       The length of the tag to check.
 *
 * \return              \c 0 on success, or a specific error code on failure.
 */
int mbedtls_cipher_check_tag( mbedtls_cipher_context_t *ctx,
                      const unsigned char *tag, size_t tag_len );
#endif /* MBEDTLS_GCM_C */

/**
 * \brief               The generic all-in-one encryption/decryption function,
 *                      for all ciphers except AEAD constructs.
 *
 * \param ctx           The generic cipher context.
 * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
 * \param iv_len        The IV length for ciphers with variable-size IV.
 *                      This parameter is discarded by ciphers with fixed-size
 *                      IV.
 * \param input         The buffer holding the input data.
 * \param ilen          The length of the input data.
 * \param output        The buffer for the output data. Must be able to hold at
 *                      least \p ilen + block_size. Must not be the same buffer
 *                      as input.
 * \param olen          The length of the output data, to be updated with the
 *                      actual number of Bytes written.
 *
 * \note                Some ciphers do not use IVs nor nonce. For these
 *                      ciphers, use \p iv = NULL and \p iv_len = 0.
 *
 * \returns             \c 0 on success, or
 *                      #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
 *                      #MBEDTLS_ERR_CIPHER_FULL_BLOCK_EXPECTED if decryption
 *                      expected a full block but was not provided one, or
 *                      #MBEDTLS_ERR_CIPHER_INVALID_PADDING on invalid padding
 *                      while decrypting, or a cipher-specific error code on
 *                      failure for any other reason.
 */
int mbedtls_cipher_crypt( mbedtls_cipher_context_t *ctx,
                  const unsigned char *iv, size_t iv_len,
                  const unsigned char *input, size_t ilen,
                  unsigned char *output, size_t *olen );

#if defined(MBEDTLS_CIPHER_MODE_AEAD)
/**
 * \brief               The generic autenticated encryption (AEAD) function.
 *
 * \param ctx           The generic cipher context.
 * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
 * \param iv_len        The IV length for ciphers with variable-size IV.
 *                      This parameter is discarded by ciphers with fixed-size IV.
 * \param ad            The additional data to authenticate.
 * \param ad_len        The length of \p ad.
 * \param input         The buffer holding the input data.
 * \param ilen          The length of the input data.
 * \param output        The buffer for the output data.
 *                      Must be able to hold at least \p ilen.
 * \param olen          The length of the output data, to be updated with the
 *                      actual number of Bytes written.
 * \param tag           The buffer for the authentication tag.
 * \param tag_len       The desired length of the authentication tag.
 *
 * \returns             \c 0 on success, or
 *                      #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
 *                      a cipher-specific error code.
 */
int mbedtls_cipher_auth_encrypt( mbedtls_cipher_context_t *ctx,
                         const unsigned char *iv, size_t iv_len,
                         const unsigned char *ad, size_t ad_len,
                         const unsigned char *input, size_t ilen,
                         unsigned char *output, size_t *olen,
                         unsigned char *tag, size_t tag_len );

/**
 * \brief               The generic autenticated decryption (AEAD) function.
 *
 * \param ctx           The generic cipher context.
 * \param iv            The IV to use, or NONCE_COUNTER for CTR-mode ciphers.
 * \param iv_len        The IV length for ciphers with variable-size IV.
 *                      This parameter is discarded by ciphers with fixed-size IV.
 * \param ad            The additional data to be authenticated.
 * \param ad_len        The length of \p ad.
 * \param input         The buffer holding the input data.
 * \param ilen          The length of the input data.
 * \param output        The buffer for the output data.
 *                      Must be able to hold at least \p ilen.
 * \param olen          The length of the output data, to be updated with the
 *                      actual number of Bytes written.
 * \param tag           The buffer holding the authentication tag.
 * \param tag_len       The length of the authentication tag.
 *
 * \returns             \c 0 on success, or
 *                      #MBEDTLS_ERR_CIPHER_BAD_INPUT_DATA, or
 *                      #MBEDTLS_ERR_CIPHER_AUTH_FAILED if data is not authentic,
 *                      or a cipher-specific error code on failure for any other reason.
 *
 * \note                If the data is not authentic, then the output buffer
 *                      is zeroed out to prevent the unauthentic plaintext being
 *                      used, making this interface safer.
 */
int mbedtls_cipher_auth_decrypt( mbedtls_cipher_context_t *ctx,
                         const unsigned char *iv, size_t iv_len,
                         const unsigned char *ad, size_t ad_len,
                         const unsigned char *input, size_t ilen,
                         unsigned char *output, size_t *olen,
                         const unsigned char *tag, size_t tag_len );
#endif /* MBEDTLS_CIPHER_MODE_AEAD */

#ifdef __cplusplus
}
#endif

#endif /* MBEDTLS_CIPHER_H */