Hannes Tschofenig
Example program to test AES-GCM functionality. Used for a workshop
gcm.h File Reference
Galois/Counter mode for 128-bit block ciphers. More...
Go to the source code of this file.
Data Structures | |
| struct | gcm_context |
| GCM context structure. More... | |
Functions | |
| int | gcm_init (gcm_context *ctx, cipher_id_t cipher, const unsigned char *key, unsigned int keysize) |
| GCM initialization (encryption) | |
| 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) |
| GCM buffer encryption/decryption using a block cipher. | |
| 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) |
| GCM buffer authenticated decryption using a block cipher. | |
| int | gcm_starts (gcm_context *ctx, int mode, const unsigned char *iv, size_t iv_len, const unsigned char *add, size_t add_len) |
| Generic GCM stream start function. | |
| int | gcm_update (gcm_context *ctx, size_t length, const unsigned char *input, unsigned char *output) |
| Generic GCM update function. | |
| int | gcm_finish (gcm_context *ctx, unsigned char *tag, size_t tag_len) |
| Generic GCM finalisation function. | |
| void | gcm_free (gcm_context *ctx) |
| Free a GCM context and underlying cipher sub-context. | |
| int | gcm_self_test (int verbose) |
| Checkup routine. | |
Detailed Description
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.
Definition in file gcm.h.
Function Documentation
| 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 | ||
| ) |
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.
- Parameters:
-
ctx GCM context length length of the input data iv initialization vector iv_len length of IV add additional data add_len length of additional data tag buffer holding the tag tag_len length of the tag input buffer holding the input data output buffer for holding the output data
- Returns:
- 0 if successful and authenticated, POLARSSL_ERR_GCM_AUTH_FAILED if tag does not match
| 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 | ||
| ) |
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.
- Parameters:
-
ctx GCM context mode GCM_ENCRYPT or GCM_DECRYPT length length of the input data iv initialization vector iv_len length of IV add additional data add_len length of additional data input buffer holding the input data output buffer for holding the output data tag_len length of the tag to generate tag buffer for holding the tag
- Returns:
- 0 if successful
| int gcm_finish | ( | gcm_context * | ctx, |
| unsigned char * | tag, | ||
| size_t | tag_len | ||
| ) |
Generic GCM finalisation function.
Wraps up the GCM stream and generates the tag. The tag can have a maximum length of 16 bytes.
- Parameters:
-
ctx GCM context tag buffer for holding the tag (may be NULL if tag_len is 0) tag_len length of the tag to generate
- Returns:
- 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT
| void gcm_free | ( | gcm_context * | ctx ) |
| int gcm_init | ( | gcm_context * | ctx, |
| cipher_id_t | cipher, | ||
| const unsigned char * | key, | ||
| unsigned int | keysize | ||
| ) |
| int gcm_self_test | ( | int | verbose ) |
| int gcm_starts | ( | gcm_context * | ctx, |
| int | mode, | ||
| const unsigned char * | iv, | ||
| size_t | iv_len, | ||
| const unsigned char * | add, | ||
| size_t | add_len | ||
| ) |
| int gcm_update | ( | gcm_context * | ctx, |
| size_t | length, | ||
| const unsigned char * | input, | ||
| unsigned char * | output | ||
| ) |
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.
- Parameters:
-
ctx GCM context length length of the input data input buffer holding the input data output buffer for holding the output data
- Returns:
- 0 if successful or POLARSSL_ERR_GCM_BAD_INPUT
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