- Added base Galois/Counter mode (GCM) for AES
diff --git a/include/polarssl/config.h b/include/polarssl/config.h
index 62663ce..c65bcd8 100644
--- a/include/polarssl/config.h
+++ b/include/polarssl/config.h
@@ -448,6 +448,17 @@
#define POLARSSL_ERROR_C
/**
+ * \def POLARSSL_GCM_C
+ *
+ * Enable the Galois/Counter Mode (GCM) for AES
+ *
+ * Module: library/gcm.c
+ *
+ * Requires: POLARSSL_AES_C
+ */
+#define POLARSSL_GCM_C
+
+/**
* \def POLARSSL_HAVEGE_C
*
* Enable the HAVEGE random generator.
diff --git a/include/polarssl/error.h b/include/polarssl/error.h
index e2e91f9..4145a50 100644
--- a/include/polarssl/error.h
+++ b/include/polarssl/error.h
@@ -49,6 +49,7 @@
*
* Module Nr Codes assigned
* MPI 7 0x0002-0x0010
+ * GCM 1 0x0012-0x0012
* AES 2 0x0020-0x0022
* CAMELLIA 2 0x0024-0x0026
* XTEA 1 0x0028-0x0028
diff --git a/include/polarssl/gcm.h b/include/polarssl/gcm.h
new file mode 100644
index 0000000..14b04d2
--- /dev/null
+++ b/include/polarssl/gcm.h
@@ -0,0 +1,132 @@
+/**
+ * \file gcm.h
+ *
+ * \brief Galois/Counter mode for AES
+ *
+ * Copyright (C) 2006-2012, 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 "aes.h"
+
+#include <stdint.h>
+
+#define GCM_ENCRYPT 1
+#define GCM_DECRYPT 0
+
+#define POLARSSL_ERR_GCM_AUTH_FAILED -0x0012 /**< Authenticated decryption failed. */
+
+/**
+ * \brief GCM context structure
+ */
+typedef struct {
+ aes_context aes_ctx; /*!< AES context used */
+ uint64_t HL[16]; /*!< Precalculated HTable */
+ uint64_t HH[16]; /*!< Precalculated HTable */
+}
+gcm_context;
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief GCM initialization (encryption)
+ *
+ * \param ctx GCM context to be initialized
+ * \param key encryption key
+ * \param keysize must be 128, 192 or 256
+ *
+ * \return 0 if successful, or POLARSSL_ERR_AES_INVALID_KEY_LENGTH
+ */
+int gcm_init( gcm_context *ctx, const unsigned char *key, unsigned int keysize );
+
+/**
+ * \brief GCM buffer encryption/decryption using AES
+ *
+ * \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 AES
+ *
+ * \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 Checkup routine
+ *
+ * \return 0 if successful, or 1 if the test failed
+ */
+int gcm_self_test( int verbose );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* gcm.h */