insereated GPLv3 stub

[avr-crypto-lib.git] / cast5.c

diff --git a/cast5.c b/cast5.c
index ebe1ce69d1bdb09d297b0945ae1225e048f36479..a938bfb37118a4661a89dde1f09b09cdf947baba 100644 (file)
--- a/cast5.c
+++ b/cast5.c
@@ -1,22 +1,43 @@
+/* cast5.c */
+/*
+    This file is part of the Crypto-avr-lib/microcrypt-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:       cast5.c
- * Author:     Daniel Otte
- * Date:       26.07.2006
- * License: GPL
- * Description: Implementation of the CAST5 (aka CAST-128) cipher algorithm as described in RFC 2144
+ * \file       cast5.c
+ * \author     Daniel Otte
+ * \date       26.07.2006
+ * \par License:
+ *  GPL
+ * \brief Implementation of the CAST5 (aka CAST-128) cipher algorithm as described in RFC 2144
  * 
  */
- //pgm_read_dword
  
  #include <stdint.h>
  #include <string.h>
  #include "cast5.h"
  #include "config.h"
- #include "uart.h"
  #include "debug.h"
  
  #undef DEBUG
  
+ #ifdef DEBUG
+  #include "uart.h"
+ #endif
+ 
 #include "cast5-sbox.h"
 
 
@@ -85,7 +106,12 @@ void cast5_init_rM(uint8_t *klo, uint8_t *khi, uint8_t offset, uint8_t *src, boo
 
 
 
-
+/**
+ * \brief sets up round keys (context) for cast5 en/decryption.
+ * @param s Pointer to cast5 context.
+ * @param key Pointer to binary key.
+ * @param keylength length of keydata in bits.
+ */
 void cast5_init(cast5_ctx_t* s, uint8_t* key, uint8_t keylength){
         /* we migth return if the key is valid and if setup was sucessfull */
        uint32_t x[4], z[4];
@@ -94,7 +120,9 @@ void cast5_init(cast5_ctx_t* s, uint8_t* key, uint8_t keylength){
        s->shortkey = (keylength<=80);
        /* littel endian only! */
        memset(&(x[0]), 0 ,16); /* set x to zero */
-       memcpy(&(x[0]), key, keylength/8);
+       if(keylength > 128)
+               keylength=128;
+       memcpy(&(x[0]), key, (keylength+7)/8);
        
 
        /* todo: merge a and b and compress the whole stuff */
@@ -203,8 +231,10 @@ uint32_t cast5_f2(uint32_t d, uint32_t m, uint8_t r){
        return (((ia - ib) + ic) ^ id);
 #else
        
-       return (((pgm_read_dword(&s1[((uint8_t*)&t)[IA]] ) - pgm_read_dword(&s2[((uint8_t*)&t)[IB]] )) 
-               + pgm_read_dword(&s3[((uint8_t*)&t)[IC]] )) ^ pgm_read_dword(&s4[((uint8_t*)&t)[ID]]));
+       return (((pgm_read_dword(&s1[((uint8_t*)&t)[IA]]) 
+               - pgm_read_dword(&s2[((uint8_t*)&t)[IB]]) ) 
+                   + pgm_read_dword(&s3[((uint8_t*)&t)[IC]]) ) 
+                   ^ pgm_read_dword(&s4[((uint8_t*)&t)[ID]]) );
 
 #endif
 }
@@ -237,8 +267,13 @@ uint32_t cast5_f3(uint32_t d, uint32_t m, uint8_t r){
 #endif
 }
 
+/*************************************************************************/
 
-
+/**
+ * \brief encrypts a datablock with cast5
+ * @param s Pointer to cast5 roundkeys (context)
+ * @param block Pointer to datablock
+ */
 void cast5_enc(cast5_ctx_t *s, void* block){
        uint32_t l,r, x, y;
        uint8_t i;
@@ -261,7 +296,13 @@ void cast5_enc(cast5_ctx_t *s, void* block){
        ((uint32_t*)block)[1]=l;
 }
 
+/*************************************************************************/
 
+/**
+ * \brief decrypts a datablock with cast5
+ * @param s Pointer to cast5 roundkeys (context)
+ * @param block Pointer to datablock
+ */
 void cast5_dec(cast5_ctx_t *s, void* block){
        uint32_t l,r, x, y;
        int8_t i, rounds;