X-Git-Url: https://git.cryptolib.org/?a=blobdiff_plain;f=sha256.h;h=24960a3a43d9325d3cbb01ea15c4f2a7e6b31684;hb=8f855d283a31a468ea014774c4723a8b77b81644;hp=82606afda8b5ff0328d0143e547b0d2f43300c01;hpb=61444fd31d322390f89b2c3955728eeea1193a67;p=avr-crypto-lib.git

diff --git a/sha256.h b/sha256.h
index 82606af..24960a3 100644
--- a/sha256.h
+++ b/sha256.h
@@ -1,9 +1,26 @@
+/* sha256.h */
+/*
+    This file is part of the AVR-Crypto-Lib.
+    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+
+    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 3 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, see <http://www.gnu.org/licenses/>.
+*/
 /**
- * \file		sha256-asm.h
- * \author		Daniel Otte 
- * \date		2006-05-16
- * \par License	
- * GPL
+ * \file	sha256.h
+ * \author  Daniel Otte 
+ * \date    2006-05-16
+ * \license	GPLv3 or later
  * 
  */
 
@@ -15,33 +32,91 @@
 
 #include <stdint.h>
 
+/** \def SHA256_HASH_BITS
+ * defines the size of a SHA-256 hash value in bits
+ */
+
+/** \def SHA256_HASH_BYTES
+ * defines the size of a SHA-256 hash value in bytes
+ */
+
+/** \def SHA256_BLOCK_BITS
+ * defines the size of a SHA-256 input block in bits
+ */
+
+/** \def SHA256_BLOCK_BYTES
+ * defines the size of a SHA-256 input block in bytes
+ */
 
 #define SHA256_HASH_BITS  256
+#define SHA256_HASH_BYTES (SHA256_HASH_BITS/8)
 #define SHA256_BLOCK_BITS 512
+#define SHA256_BLOCK_BYTES (SHA256_BLOCK_BITS/8)
 
-/**
- * \brief sha256 context type
+/** \typedef sha256_ctx_t
+ * \brief SHA-256 context type
  * 
+ * A variable of this type may hold the state of a SHA-256 hashing process
  */
 typedef struct {
 	uint32_t h[8];
 	uint64_t length;
 } sha256_ctx_t;
 
-typedef uint8_t sha256_hash_t[SHA256_HASH_BITS/8];
+/** \typedef sha256_hash_t
+ * \brief SHA-256 hash value type
+ * 
+ * A variable of this type may hold the hash value produced by the
+ * sha256_ctx2hash(sha256_hash_t* dest, const sha256_ctx_t* state) function.
+ */
+typedef uint8_t sha256_hash_t[SHA256_HASH_BYTES];
 
+/** \fn void sha256_init(sha256_ctx_t *state)
+ * \brief initialise a SHA-256 context
+ * 
+ * This function sets a ::sha256_ctx_t to the initial values for hashing.
+ * \param state pointer to the SHA-256 hashing context
+ */
 void sha256_init(sha256_ctx_t *state);
 
-void sha256_nextBlock (sha256_ctx_t *state, const void* block);
-void sha256_lastBlock(sha256_ctx_t *state, const void* block, uint16_t length);
+/** \fn void sha256_nextBlock (sha256_ctx_t* state, const void* block)
+ * \brief update the context with a given block
+ * 
+ * This function updates the SHA-256 hash context by processing the given block
+ * of fixed length.
+ * \param state pointer to the SHA-256 hash context
+ * \param block pointer to the block of fixed length (512 bit = 64 byte)
+ */
+void sha256_nextBlock (sha256_ctx_t* state, const void* block);
 
-void sha256_ctx2hash(sha256_hash_t *dest, const sha256_ctx_t *state);
+/** \fn void sha256_lastBlock(sha256_ctx_t* state, const void* block, uint16_t length_b)
+ * \brief finalize the context with the given block 
+ * 
+ * This function finalizes the SHA-256 hash context by processing the given block
+ * of variable length.
+ * \param state pointer to the SHA-256 hash context
+ * \param block pointer to the block of fixed length (512 bit = 64 byte)
+ * \param length_b the length of the block in bits
+ */
+void sha256_lastBlock(sha256_ctx_t* state, const void* block, uint16_t length_b);
 
-/*
- * length in bits!
+/** \fn void sha256_ctx2hash(sha256_hash_t* dest, const sha256_ctx_t* state)
+ * \brief convert the hash state into the hash value
+ * This function reads the context and writes the hash value to the destination
+ * \param dest pointer to the location where the hash value should be written
+ * \param state pointer to the SHA-256 hash context
  */
-void sha256(sha256_hash_t *dest, const void* msg, uint32_t length);
-uint32_t change_endian32(uint32_t x);
+void sha256_ctx2hash(sha256_hash_t* dest, const sha256_ctx_t* state);
 
+/** \fn void sha256(sha256_hash_t* dest, const void* msg, uint32_t length_b)
+ * \brief simple SHA-256 hashing function for direct hashing
+ * 
+ * This function automaticaly hashes a given message of arbitary length with
+ * the SHA-256 hashing algorithm.
+ * \param dest pointer to the location where the hash value is going to be written to
+ * \param msg pointer to the message thats going to be hashed
+ * \param length_b length of the message in bits
+ */
+void sha256(sha256_hash_t* dest, const void* msg, uint32_t length_b);
 
 #endif /*SHA256_H_*/