Change md2_end prototype. Remove a unneeded memcpy in md2_end. Add comments.

[bertos.git] / algos / md2.c

diff --git a/algos/md2.c b/algos/md2.c
index 176efe6994ca4cb735458c3ae542b06f9bdf79c0..338005c40c05937ad91716d771979f37d9285d46 100755 (executable)
--- a/algos/md2.c
+++ b/algos/md2.c
@@ -13,6 +13,21 @@
 
 /*#*
  *#* $Log$
+ *#* Revision 1.10  2007/02/02 15:37:45  asterix
+ *#* Change md2_end prototype. Remove a unneeded memcpy in md2_end. Add comments.
+ *#*
+ *#* Revision 1.9  2007/02/02 13:10:01  asterix
+ *#* Fix some bugs in md2_pad and md2_update fuction.
+ *#*
+ *#* Revision 1.8  2007/02/01 14:45:56  asterix
+ *#* Rewrite md2_update function and fix some bug.
+ *#*
+ *#* Revision 1.7  2007/01/31 18:04:15  asterix
+ *#* Write md2_end function
+ *#*
+ *#* Revision 1.4  2007/01/31 13:51:57  asterix
+ *#* Write md2_compute function.
+ *#*
  *#* Revision 1.2  2007/01/30 17:31:44  asterix
  *#* Add function prototypes.
  *#*
@@ -21,8 +36,17 @@
  *#*
  *#*/
 
+#include "md2.h"
+
+#include <string.h>           //memset(), memcpy();
+#include <cfg/compiler.h>
+#include <cfg/debug.h>        //ASSERT()
+#include <cfg/macros.h>       //MIN()
+
+
 /*
- * Array of 256 byte pemutation contructed from digits of pi.
+ * Official array of 256 byte pemutation contructed from digits of pi, defined
+ * in the RFC 1319.
  */
 static uint8_t md2_perm[256] = {
   41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
@@ -45,30 +69,163 @@ static uint8_t md2_perm[256] = {
   31, 26, 219, 153, 141, 51, 159, 17, 131, 20
 };
 
-static void md2_pad(void *block)
+/**
+ * Pad function. Put len_pad unsigned char in
+ * input block.
+ */
+static void md2_pad(void *_block, size_t len_pad)
 {
+       uint8_t *block;
+
+       block = (uint8_t *)_block;
+
+       ASSERT(len_pad <= CONFIG_MD2_BLOCK_LEN);
+
+       /*
+        * Fill input block with len_pad char.
+        */
+       memset(block, len_pad, len_pad);
 
 }
 
-static void md2_compute(void *state, void *checksum, void *block)
+static void md2_compute(void *_state, void *_checksum, void *_block)
 {
+       int i = 0;
+       uint16_t t = 0;
+       uint8_t compute_array[COMPUTE_ARRAY_LEN];
+       uint8_t *state;
+       uint8_t *checksum;
+       uint8_t *block;
+
+       state = (uint8_t *)_state;
+       checksum  = (uint8_t *)_checksum;
+       block = (uint8_t *)_block;
+
+       /*
+        * Copy state and checksum context in compute array.
+        */
+       memcpy(compute_array, state, CONFIG_MD2_BLOCK_LEN);
+       memcpy(compute_array + CONFIG_MD2_BLOCK_LEN, block, CONFIG_MD2_BLOCK_LEN);
+
+       /*
+        * Fill compute array with state XOR block
+        */
+       for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
+               compute_array[i + (CONFIG_MD2_BLOCK_LEN * 2)] = state[i] ^ block[i];
 
+       /*
+        * Encryt block.
+        */
+       for(i = 0; i < NUM_COMPUTE_ROUNDS; i++)
+       {
+               for(int j = 0; j < COMPUTE_ARRAY_LEN; j++)
+               {
+                       compute_array[j] ^= md2_perm [t];
+                       t = compute_array[j];
+               }
+
+               t = (t + i) & 0xff; //modulo 256.
+       }
+       /*
+        * Update checksum.
+        */
+       t = checksum[CONFIG_MD2_BLOCK_LEN - 1];
+
+       for(i = 0; i < CONFIG_MD2_BLOCK_LEN; i++)
+       {
+               checksum[i]  ^= md2_perm [block[i] ^ t];
+               t = checksum[i];
+       }
+
+       /*
+        * Update state and clean compute array.
+        */
+       memcpy(state, compute_array, CONFIG_MD2_BLOCK_LEN);
+       memset(compute_array, 0, sizeof(compute_array));
 }
 
+/**
+ * Algorithm initialization.
+ *
+ * \param empty context.
+ */
 void md2_init(Md2Context *context)
 {
-       context->counter=0;
-       memset(context->state, 0, sizeof(context->state));
-       memset(context->checksum, 0, sizeof(context->checksum));
+
+       memset(context, 0, sizeof(Md2Context));
 
 }
 
-void md2_update(Md2Context *context, void *block_in, size_t block_len)
+/**
+ * Update block.
+ */
+void md2_update(Md2Context *context, void *_block_in, size_t block_len)
 {
 
-}
+       uint8_t *block_in;
+
+       /*
+        * Choose a number of block that fill input context buffer.
+        */
+       size_t missing_len = MIN(block_len, CONFIG_MD2_BLOCK_LEN - context->counter);
+
+       block_in = (uint8_t *)_block_in;
+
+       while(block_len > 0)
+       {
+               /*
+                * Copy in the buffer input block.
+                */
+               memcpy(&context->buffer[context->counter], block_in, missing_len);
+
+               /*
+                * Update a context counter, input block length and remaning 
+                * context buffer block lenght.
+                */
+               context->counter += missing_len;
+               block_len -= missing_len;
+               block_in += missing_len;
+
+               /*
+                * If buffer is full, compute it.
+                */
+               if (context->counter >= CONFIG_MD2_BLOCK_LEN)
+               {
+                       md2_compute(context->state, context->checksum, context->buffer);
+                       context->counter = 0;
+               }
+       }
 
-void md2_end(Md2Context *context, void *msg_digest)
+
+}
+/**
+ * Ends an MD2 message digest operation.
+ * This fuction take an context and return a pointer
+ * to context state.
+ *
+ * \param context in input.
+ * \return a pointer to context state (message digest).
+ */
+uint8_t  *md2_end(Md2Context *context)
 {
 
+       uint8_t buf[CONFIG_MD2_BLOCK_LEN];
+
+       /*
+        * Fill remaning empty context buffer.
+        */
+       md2_pad(buf, CONFIG_MD2_BLOCK_LEN - context->counter);
+
+       /*
+        * Update context buffer and compute it.
+        */
+       md2_update(context, buf, CONFIG_MD2_BLOCK_LEN - context->counter);
+
+       /*
+        * Add context checksum to message input.
+        */
+       md2_update(context, context->checksum, CONFIG_MD2_BLOCK_LEN);
+
+
+       return context->state; //return a pointer to message digest.
 }