0d107e183e
The interface for this is very similar to upstream, but the code is quite different. Support for “resuming” (i.e. calling |CMAC_Final| and then computing the CMAC for an extension of the message) has been dropped. Also, calling |CMAC_Init| with magic argument to reset it has been replaced with |CMAC_Reset|. Lastly, a one-shot function has been added because it can save an allocation and that's what most callers actually appear to want to do. Change-Id: I9345220218bdb16ebe6ca356928d7c6f055d83f6 Reviewed-on: https://boringssl-review.googlesource.com/4630 Reviewed-by: David Benjamin <davidben@chromium.org> Reviewed-by: Adam Langley <agl@google.com>
77 lines
2.8 KiB
C
77 lines
2.8 KiB
C
/* Copyright (c) 2015, Google Inc.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
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* OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
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* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
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#ifndef OPENSSL_HEADER_CMAC_H
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#define OPENSSL_HEADER_CMAC_H
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#include <openssl/base.h>
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#if defined(__cplusplus)
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extern "C" {
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#endif
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/* CMAC.
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*
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* CMAC is a MAC based on AES-CBC and defined in
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* https://tools.ietf.org/html/rfc4493#section-2.3. */
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/* One-shot functions. */
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/* AES_CMAC calculates the 16-byte, CMAC authenticator of |in_len| bytes of
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* |in| and writes it to |out|. The |key_len| may be 16 or 32 bytes to select
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* between AES-128 and AES-256. It returns one on success or zero on error. */
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OPENSSL_EXPORT int AES_CMAC(uint8_t out[16], const uint8_t *key, size_t key_len,
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const uint8_t *in, size_t in_len);
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/* Incremental interface. */
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/* CMAC_CTX_new allocates a fresh |CMAC_CTX| and returns it, or NULL on
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* error. */
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OPENSSL_EXPORT CMAC_CTX *CMAC_CTX_new(void);
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/* CMAC_CTX_free frees a |CMAC_CTX|. */
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OPENSSL_EXPORT void CMAC_CTX_free(CMAC_CTX *ctx);
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/* CMAC_Init configures |ctx| to use the given |key| and |cipher|. The CMAC RFC
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* only specifies the use of AES-128 thus |key_len| should be 16 and |cipher|
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* should be |EVP_aes_128_cbc()|. However, this implementation also supports
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* AES-256 by setting |key_len| to 32 and |cipher| to |EVP_aes_256_cbc()|. The
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* |engine| argument is ignored.
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*
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* It returns one on success or zero on error. */
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OPENSSL_EXPORT int CMAC_Init(CMAC_CTX *ctx, const void *key, size_t key_len,
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const EVP_CIPHER *cipher, ENGINE *engine);
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/* CMAC_Reset resets |ctx| so that a fresh message can be authenticated. */
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OPENSSL_EXPORT int CMAC_Reset(CMAC_CTX *ctx);
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/* CMAC_Update processes |in_len| bytes of message from |in|. It returns one on
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* success or zero on error. */
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OPENSSL_EXPORT int CMAC_Update(CMAC_CTX *ctx, const uint8_t *in, size_t in_len);
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/* CMAC_Final sets |*out_len| to 16 and, if |out| is not NULL, writes 16 bytes
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* of authenticator to it. It returns one on success or zero on error. */
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OPENSSL_EXPORT int CMAC_Final(CMAC_CTX *ctx, uint8_t *out, size_t *out_len);
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#if defined(__cplusplus)
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} /* extern C */
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#endif
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#endif /* OPENSSL_HEADER_CBC_H */
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