| /** |
| * \file gcm.h |
| * |
| * \brief Galois/Counter mode for 128-bit block ciphers |
| * |
| * Copyright (C) 2006-2013, Brainspark B.V. |
| * |
| * This file is part of PolarSSL (http://www.polarssl.org) |
| * Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org> |
| * |
| * All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License along |
| * with this program; if not, write to the Free Software Foundation, Inc., |
| * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. |
| */ |
| #ifndef POLARSSL_GCM_H |
| #define POLARSSL_GCM_H |
| |
| #include "cipher.h" |
| |
| #ifdef _MSC_VER |
| #include <basetsd.h> |
| typedef UINT64 uint64_t; |
| #else |
| #include <stdint.h> |
| #endif |
| |
| #define GCM_ENCRYPT 1 |
| #define GCM_DECRYPT 0 |
| |
| #define POLARSSL_ERR_GCM_AUTH_FAILED -0x0012 /**< Authenticated decryption failed. */ |
| #define POLARSSL_ERR_GCM_BAD_INPUT -0x0014 /**< Bad input parameters to function. */ |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| /** |
| * \brief GCM context structure |
| */ |
| typedef struct { |
| cipher_context_t cipher_ctx;/*!< cipher context used */ |
| uint64_t HL[16]; /*!< Precalculated HTable */ |
| uint64_t HH[16]; /*!< Precalculated HTable */ |
| uint64_t len; /*!< Total data length */ |
| uint64_t add_len; /*!< Total add length */ |
| unsigned char base_ectr[16];/*!< First ECTR for tag */ |
| unsigned char y[16]; /*!< Y working value */ |
| unsigned char buf[16]; /*!< buf working value */ |
| int mode; /*!< Encrypt or Decrypt */ |
| } |
| gcm_context; |
| |
| /** |
| * \brief GCM initialization (encryption) |
| * |
| * \param ctx GCM context to be initialized |
| * \param cipher cipher to use (a 128-bit block cipher) |
| * \param key encryption key |
| * \param keysize must be 128, 192 or 256 |
| * |
| * \return 0 if successful, or a cipher specific error code |
| */ |
| int gcm_init( gcm_context *ctx, cipher_id_t cipher, const unsigned char *key, |
| unsigned int keysize ); |
| |
| /** |
| * \brief GCM buffer encryption/decryption using a block cipher |
| * |
| * \note On encryption, the output buffer can be the same as the input buffer. |
| * On decryption, the output buffer cannot be the same as input buffer. |
| * If buffers overlap, the output buffer must trail at least 8 bytes |
| * behind the input buffer. |
| * |
| * \param ctx GCM context |
| * \param mode GCM_ENCRYPT or GCM_DECRYPT |
| * \param length length of the input data |
| * \param iv initialization vector |
| * \param iv_len length of IV |
| * \param add additional data |
| * \param add_len length of additional data |
| * \param input buffer holding the input data |
| * \param output buffer for holding the output data |
| * \param tag_len length of the tag to generate |
| * \param tag buffer for holding the tag |
| * |
| * \return 0 if successful |
| */ |
| int gcm_crypt_and_tag( gcm_context *ctx, |
| int mode, |
| size_t length, |
| const unsigned char *iv, |
| size_t iv_len, |
| const unsigned char *add, |
| size_t add_len, |
| const unsigned char *input, |
| unsigned char *output, |
| size_t tag_len, |
| unsigned char *tag ); |
| |
| /** |
| * \brief GCM buffer authenticated decryption using a block cipher |
| * |
| * \note On decryption, the output buffer cannot be the same as input buffer. |
| * If buffers overlap, the output buffer must trail at least 8 bytes |
| * behind the input buffer. |
| * |
| * \param ctx GCM context |
| * \param length length of the input data |
| * \param iv initialization vector |
| * \param iv_len length of IV |
| * \param add additional data |
| * \param add_len length of additional data |
| * \param tag buffer holding the tag |
| * \param tag_len length of the tag |
| * \param input buffer holding the input data |
| * \param output buffer for holding the output data |
| * |
| * \return 0 if successful and authenticated, |
| * POLARSSL_ERR_GCM_AUTH_FAILED if tag does not match |
| */ |
| int gcm_auth_decrypt( gcm_context *ctx, |
| size_t length, |
| const unsigned char *iv, |
| size_t iv_len, |
| const unsigned char *add, |
| size_t add_len, |
| const unsigned char *tag, |
| size_t tag_len, |
| const unsigned char *input, |
| unsigned char *output ); |
| |
| /** |
| * \brief Generic GCM stream start function |
| * |
| * \param ctx GCM context |
| * \param mode GCM_ENCRYPT or GCM_DECRYPT |
| * \param iv initialization vector |
| * \param iv_len length of IV |
| * \param add additional data (or NULL if length is 0) |
| * \param add_len length of additional data |
| * |
| * \return 0 if successful |
| */ |
| int gcm_starts( gcm_context *ctx, |
| int mode, |
| const unsigned char *iv, |
| size_t iv_len, |
| const unsigned char *add, |
| size_t add_len ); |
| |
| /** |
| * \brief Generic GCM update function. Encrypts/decrypts using the |
| * given GCM context. Expects input to be a multiple of 16 |
| * bytes! Only the last call before gcm_finish() can be less |
| * than 16 bytes! |
| * |
| * \note On decryption, the output buffer cannot be the same as input buffer. |
| * If buffers overlap, the output buffer must trail at least 8 bytes |
| * behind the input buffer. |
| * |
| * \param ctx GCM context |
| * \param length length of the input data |
| * \param input buffer holding the input data |
| * \param output buffer for holding the output data |
| * |
| * \return 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT |
| */ |
| int gcm_update( gcm_context *ctx, |
| size_t length, |
| const unsigned char *input, |
| unsigned char *output ); |
| |
| /** |
| * \brief Generic GCM finalisation function. Wraps up the GCM stream |
| * and generates the tag. The tag can have a maximum length of |
| * 16 bytes. |
| * |
| * \param ctx GCM context |
| * \param tag buffer for holding the tag (may be NULL if tag_len is 0) |
| * \param tag_len length of the tag to generate |
| * |
| * \return 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT |
| */ |
| int gcm_finish( gcm_context *ctx, |
| unsigned char *tag, |
| size_t tag_len ); |
| |
| /** |
| * \brief Free a GCM context and underlying cipher sub-context |
| * |
| * \param ctx |
| */ |
| void gcm_free( gcm_context *ctx ); |
| |
| /** |
| * \brief Checkup routine |
| * |
| * \return 0 if successful, or 1 if the test failed |
| */ |
| int gcm_self_test( int verbose ); |
| |
| #ifdef __cplusplus |
| } |
| #endif |
| |
| #endif /* gcm.h */ |