fixing E-Mail-Address & Copyright

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

diff --git a/arcfour/arcfour.c b/arcfour/arcfour.c
index 0d929efa899edfeba59634a76688970cabcdbdb1..fbb644f1446b8db81fcc95dc644467bd6179cc64 100644 (file)
--- a/arcfour/arcfour.c
+++ b/arcfour/arcfour.c
@@ -1,25 +1,25 @@
 /* arcfour.c */
 /*
-    This file is part of the AVR-Crypto-Lib.
-    Copyright (C) 2008  Daniel Otte (daniel.otte@rub.de)
+ This file is part of the AVR-Crypto-Lib.
+ Copyright (C) 2006-2015 Daniel Otte (bg@nerilex.org)
 
-    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 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.
+ 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/>.
-*/
+ 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:        arcfour.c
  * Author:      Daniel Otte
- * email:       daniel.otte@rub.de
+ * email:       bg@nerilex.org
  * Date:        2006-06-07
  * License:     GPLv3 or later
  * Description: Implementation of the ARCFOUR (RC4 compatible) stream cipher algorithm.
@@ -33,32 +33,42 @@
  * length is length of key in bytes!
  */
 
-void arcfour_init(const void *key, uint16_t length_b, arcfour_ctx_t *ctx){
-       uint8_t t;
-       uint8_t length_B = length_b/8;
-       uint16_t x,y=0;
-       for(x=0; x<= 255; ++x)
-               ctx->s[x]=x;
+void arcfour_init(const void *key, uint16_t length_b, arcfour_ctx_t *ctx)
+{
+    uint8_t t;
+    const uint8_t length_B = length_b / 8;
+    uint8_t nidx = length_B;
+    uint8_t x = 0, y = 0;
+    const uint8_t *kptr = (const uint8_t*) key;
+    do {
+        ctx->s[x] = x;
+    } while ((uint8_t) ++x);
+
+    do {
+        y += ctx->s[x] + *kptr++;
+        if (!--nidx) {
+            kptr = (const uint8_t*) key;
+            nidx = length_B;
+        }
+        y &= 0xff;
+        /* ctx->s[y] <--> ctx->s[x] */
+        t = ctx->s[y];
+        ctx->s[y] = ctx->s[x];
+        ctx->s[x] = t;
+    } while ((uint8_t) ++x);
 
-       for(x=0; x<= 255; ++x){
-               y += ctx->s[x] + ((uint8_t*)key)[x % length_B];
-               y &= 0xff;
-               /* ctx->s[y] <--> ctx->s[x] */
-               t = ctx->s[y];
-               ctx->s[y] = ctx->s[x];
-               ctx->s[x] = t;
-       }
-       ctx->i = ctx->j = 0;
+    ctx->i = ctx->j = 0;
 }
 
-uint8_t arcfour_gen(arcfour_ctx_t *ctx){
-       uint8_t t;
-       ctx->i++;
-       ctx->j += ctx->s[ctx->i];
-       /* ctx->s[i] <--> ctx->s[j] */
-       t = ctx->s[ctx->j];
-       ctx->s[ctx->j] = ctx->s[ctx->i];
-       ctx->s[ctx->i] = t;
-       return ctx->s[(ctx->s[ctx->j] + ctx->s[ctx->i]) & 0xff];
+uint8_t arcfour_gen(arcfour_ctx_t *ctx)
+{
+    uint8_t t;
+    ctx->i++;
+    ctx->j += ctx->s[ctx->i];
+    /* ctx->s[i] <--> ctx->s[j] */
+    t = ctx->s[ctx->j];
+    ctx->s[ctx->j] = ctx->s[ctx->i];
+    ctx->s[ctx->i] = t;
+    return ctx->s[(ctx->s[ctx->j] + ctx->s[ctx->i]) & 0xff];
 }