1/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2 * All rights reserved.
3 *
4 * This package is an SSL implementation written
5 * by Eric Young (eay@cryptsoft.com).
6 * The implementation was written so as to conform with Netscapes SSL.
7 *
8 * This library is free for commercial and non-commercial use as long as
9 * the following conditions are aheared to. The following conditions
10 * apply to all code found in this distribution, be it the RC4, RSA,
11 * lhash, DES, etc., code; not just the SSL code. The SSL documentation
12 * included with this distribution is covered by the same copyright terms
13 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14 *
15 * Copyright remains Eric Young's, and as such any Copyright notices in
16 * the code are not to be removed.
17 * If this package is used in a product, Eric Young should be given attribution
18 * as the author of the parts of the library used.
19 * This can be in the form of a textual message at program startup or
20 * in documentation (online or textual) provided with the package.
21 *
22 * Redistribution and use in source and binary forms, with or without
23 * modification, are permitted provided that the following conditions
24 * are met:
25 * 1. Redistributions of source code must retain the copyright
26 * notice, this list of conditions and the following disclaimer.
27 * 2. Redistributions in binary form must reproduce the above copyright
28 * notice, this list of conditions and the following disclaimer in the
29 * documentation and/or other materials provided with the distribution.
30 * 3. All advertising materials mentioning features or use of this software
31 * must display the following acknowledgement:
32 * "This product includes cryptographic software written by
33 * Eric Young (eay@cryptsoft.com)"
34 * The word 'cryptographic' can be left out if the rouines from the library
35 * being used are not cryptographic related :-).
36 * 4. If you include any Windows specific code (or a derivative thereof) from
37 * the apps directory (application code) you must include an acknowledgement:
38 * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 * SUCH DAMAGE.
51 *
52 * The licence and distribution terms for any publically available version or
53 * derivative of this code cannot be changed. i.e. this code cannot simply be
54 * copied and put under another distribution licence
55 * [including the GNU Public Licence.] */
56
57#ifndef OPENSSL_HEADER_HMAC_H
58#define OPENSSL_HEADER_HMAC_H
59
60#include <openssl/base.h>
61
62#include <openssl/digest.h>
63
64#if defined(__cplusplus)
65extern "C" {
66#endif
67
68
69// HMAC contains functions for constructing PRFs from Merkle–Damgård hash
70// functions using HMAC.
71
72
73// One-shot operation.
74
75// HMAC calculates the HMAC of |data_len| bytes of |data|, using the given key
76// and hash function, and writes the result to |out|. On entry, |out| must
77// contain at least |EVP_MD_size| bytes of space. The actual length of the
78// result is written to |*out_len|. An output size of |EVP_MAX_MD_SIZE| will
79// always be large enough. It returns |out| or NULL on error.
80OPENSSL_EXPORT uint8_t *HMAC(const EVP_MD *evp_md, const void *key,
81 size_t key_len, const uint8_t *data,
82 size_t data_len, uint8_t *out,
83 unsigned int *out_len);
84
85
86// Incremental operation.
87
88// HMAC_CTX_init initialises |ctx| for use in an HMAC operation. It's assumed
89// that HMAC_CTX objects will be allocated on the stack thus no allocation
90// function is provided.
91OPENSSL_EXPORT void HMAC_CTX_init(HMAC_CTX *ctx);
92
93// HMAC_CTX_new allocates and initialises a new |HMAC_CTX| and returns it, or
94// NULL on allocation failure. The caller must use |HMAC_CTX_free| to release
95// the resulting object.
96OPENSSL_EXPORT HMAC_CTX *HMAC_CTX_new(void);
97
98// HMAC_CTX_cleanup frees data owned by |ctx|. It does not free |ctx| itself.
99OPENSSL_EXPORT void HMAC_CTX_cleanup(HMAC_CTX *ctx);
100
101// HMAC_CTX_free calls |HMAC_CTX_cleanup| and then frees |ctx| itself.
102OPENSSL_EXPORT void HMAC_CTX_free(HMAC_CTX *ctx);
103
104// HMAC_Init_ex sets up an initialised |HMAC_CTX| to use |md| as the hash
105// function and |key| as the key. For a non-initial call, |md| may be NULL, in
106// which case the previous hash function will be used. If the hash function has
107// not changed and |key| is NULL, |ctx| reuses the previous key. It returns one
108// on success or zero on allocation failure.
109//
110// WARNING: NULL and empty keys are ambiguous on non-initial calls. Passing NULL
111// |key| but repeating the previous |md| reuses the previous key rather than the
112// empty key.
113OPENSSL_EXPORT int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len,
114 const EVP_MD *md, ENGINE *impl);
115
116// HMAC_Update hashes |data_len| bytes from |data| into the current HMAC
117// operation in |ctx|. It returns one.
118OPENSSL_EXPORT int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data,
119 size_t data_len);
120
121// HMAC_Final completes the HMAC operation in |ctx| and writes the result to
122// |out| and the sets |*out_len| to the length of the result. On entry, |out|
123// must contain at least |HMAC_size| bytes of space. An output size of
124// |EVP_MAX_MD_SIZE| will always be large enough. It returns one on success or
125// zero on allocation failure.
126OPENSSL_EXPORT int HMAC_Final(HMAC_CTX *ctx, uint8_t *out,
127 unsigned int *out_len);
128
129
130// Utility functions.
131
132// HMAC_size returns the size, in bytes, of the HMAC that will be produced by
133// |ctx|. On entry, |ctx| must have been setup with |HMAC_Init_ex|.
134OPENSSL_EXPORT size_t HMAC_size(const HMAC_CTX *ctx);
135
136// HMAC_CTX_copy_ex sets |dest| equal to |src|. On entry, |dest| must have been
137// initialised by calling |HMAC_CTX_init|. It returns one on success and zero
138// on error.
139OPENSSL_EXPORT int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src);
140
141// HMAC_CTX_reset calls |HMAC_CTX_cleanup| followed by |HMAC_CTX_init|.
142OPENSSL_EXPORT void HMAC_CTX_reset(HMAC_CTX *ctx);
143
144
145// Deprecated functions.
146
147OPENSSL_EXPORT int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len,
148 const EVP_MD *md);
149
150// HMAC_CTX_copy calls |HMAC_CTX_init| on |dest| and then sets it equal to
151// |src|. On entry, |dest| must /not/ be initialised for an operation with
152// |HMAC_Init_ex|. It returns one on success and zero on error.
153OPENSSL_EXPORT int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src);
154
155
156// Private functions
157
158struct hmac_ctx_st {
159 const EVP_MD *md;
160 EVP_MD_CTX md_ctx;
161 EVP_MD_CTX i_ctx;
162 EVP_MD_CTX o_ctx;
163} /* HMAC_CTX */;
164
165
166#if defined(__cplusplus)
167} // extern C
168
169#if !defined(BORINGSSL_NO_CXX)
170extern "C++" {
171
172BSSL_NAMESPACE_BEGIN
173
174BORINGSSL_MAKE_DELETER(HMAC_CTX, HMAC_CTX_free)
175
176using ScopedHMAC_CTX =
177 internal::StackAllocated<HMAC_CTX, void, HMAC_CTX_init, HMAC_CTX_cleanup>;
178
179BSSL_NAMESPACE_END
180
181} // extern C++
182#endif
183
184#endif
185
186#endif // OPENSSL_HEADER_HMAC_H
187