Diff: include/mbedtls/gcm.h

Revision:

0:cdf462088d13

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/mbedtls/gcm.h	Thu Jan 05 00:18:44 2017 +0000
@@ -0,0 +1,220 @@
+/**
+ * \file gcm.h
+ *
+ * \brief Galois/Counter mode for 128-bit block ciphers
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may
+ *  not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+#ifndef MBEDTLS_GCM_H
+#define MBEDTLS_GCM_H
+
+#include "cipher.h"
+
+#include <stdint.h>
+
+#define MBEDTLS_GCM_ENCRYPT     1
+#define MBEDTLS_GCM_DECRYPT     0
+
+#define MBEDTLS_ERR_GCM_AUTH_FAILED                       -0x0012  /**< Authenticated decryption failed. */
+#define MBEDTLS_ERR_GCM_BAD_INPUT                         -0x0014  /**< Bad input parameters to function. */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * \brief          GCM context structure
+ */
+typedef struct {
+    mbedtls_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 */
+}
+mbedtls_gcm_context;
+
+/**
+ * \brief           Initialize GCM context (just makes references valid)
+ *                  Makes the context ready for mbedtls_gcm_setkey() or
+ *                  mbedtls_gcm_free().
+ *
+ * \param ctx       GCM context to initialize
+ */
+void mbedtls_gcm_init( mbedtls_gcm_context *ctx );
+
+/**
+ * \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 keybits   must be 128, 192 or 256
+ *
+ * \return          0 if successful, or a cipher specific error code
+ */
+int mbedtls_gcm_setkey( mbedtls_gcm_context *ctx,
+                        mbedtls_cipher_id_t cipher,
+                        const unsigned char *key,
+                        unsigned int keybits );
+
+/**
+ * \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      MBEDTLS_GCM_ENCRYPT or MBEDTLS_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 mbedtls_gcm_crypt_and_tag( mbedtls_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,
+ *                 MBEDTLS_ERR_GCM_AUTH_FAILED if tag does not match
+ */
+int mbedtls_gcm_auth_decrypt( mbedtls_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      MBEDTLS_GCM_ENCRYPT or MBEDTLS_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 mbedtls_gcm_starts( mbedtls_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 mbedtls_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 MBEDTLS_ERR_GCM_BAD_INPUT
+ */
+int mbedtls_gcm_update( mbedtls_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
+ * \param tag_len   length of the tag to generate (must be at least 4)
+ *
+ * \return          0 if successful or MBEDTLS_ERR_GCM_BAD_INPUT
+ */
+int mbedtls_gcm_finish( mbedtls_gcm_context *ctx,
+                unsigned char *tag,
+                size_t tag_len );
+
+/**
+ * \brief           Free a GCM context and underlying cipher sub-context
+ *
+ * \param ctx       GCM context to free
+ */
+void mbedtls_gcm_free( mbedtls_gcm_context *ctx );
+
+/**
+ * \brief          Checkup routine
+ *
+ * \return         0 if successful, or 1 if the test failed
+ */
+int mbedtls_gcm_self_test( int verbose );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* gcm.h */