added CAST5, CAST6, RC5 and RC6

[arm-crypto-lib.git] / rc6 / rc6.c

diff --git a/rc6/rc6.c b/rc6/rc6.c
new file mode 100644 (file)
index 0000000..920c947
--- /dev/null
+++ b/rc6/rc6.c
@@ -0,0 +1,141 @@
+/* rc6.c */
+/*
+    This file is part of the ARM-Crypto-Lib.
+    Copyright (C) 2006-2010  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:       rc6.c
+ * Author:     Daniel Otte
+ * Date:       06.08.2006
+ * License: GPL
+ * Description: Implementation of the RC6 cipher algorithm.
+ *     This implementation is restricted to 32-bit words and to keys up to 65535 bit in length (but this is
+ *  quite easy to expand), but free in the choice of number of rounds (0 to 125).
+ *     so it is RC6-32/r/b
+ * THIS ONLY WORKS FOR LITTEL ENDIAN!!!
+ */
+ 
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include "rc6.h"
+ 
+#define P32 0xB7E15163         /* e -2 */
+#define Q32 0x9E3779B9         /* Golden Ratio -1 */
+ 
+uint32_t rotl32(uint32_t a, uint8_t n){
+       n &= 0x1f; /* higher rotates would not bring anything */
+       return ( (a<<n)| (a>>(32-n)) );
+}
+
+uint32_t rotr32(uint32_t a, uint8_t n){
+       n &= 0x1f; /* higher rotates would not bring anything */
+       return ( (a>>n)| (a<<(32-n)) );
+}
+ 
+void rc6_init(const void* key, uint16_t keylength_b, rc6_ctx_t *s){
+       rc6_initl(key, keylength_b, 20, s);
+}
+ 
+ 
+uint8_t rc6_initl(const void* key, uint16_t keylength_b, uint8_t rounds, rc6_ctx_t *s){
+       uint8_t i,j;
+       uint16_t v,p,c;
+       uint32_t a,b;
+       c =( keylength_b+31)/32;
+       uint32_t local_key[c];
+       if (rounds>125)
+               return 2;
+       if(!(s->S=malloc((2*rounds+4)*sizeof(uint32_t))))
+               return 1;
+       
+       s->rounds=rounds;
+       local_key[c-1] = 0;
+       memcpy(local_key, key, (keylength_b+7)/8);
+       
+       s->S[0] = P32;
+       for(i=1; i<2*rounds+4; ++i){
+               s->S[i] = s->S[i-1] + Q32;
+       }
+       
+       a=b=j=i=0;
+       v = 3 * ((c > (2*rounds+4))?c:(2*rounds+4));
+       for(p=1; p<=v; ++p){
+               a = s->S[i] = rotl32(s->S[i] + a + b, 3);
+               b = ((uint32_t*)local_key)[j] = rotl32(((uint32_t*)local_key)[j]+a+b, a+b);
+               i = (i+1) % (2*rounds+4);
+               j = (j+1) % c;
+       }
+       return 0;
+}
+ 
+void rc6_free(rc6_ctx_t *s){
+       free(s->S);
+} 
+ 
+#define LG_W 5
+#define A (((uint32_t*)block)[0])
+#define B (((uint32_t*)block)[1])
+#define C (((uint32_t*)block)[2])
+#define D (((uint32_t*)block)[3])
+ 
+void rc6_enc(void* block, rc6_ctx_t *s){
+       uint8_t i;
+       uint32_t t,u,x; /* greetings to Linux? */
+       uint32_t *p;
+       p=s->S;
+       B += *p++;
+       D += *p++;
+       i=s->rounds;
+       do{
+               t = rotl32(B * (2*B+1), LG_W);
+               u = rotl32(D * (2*D+1), LG_W);
+               A = rotl32((A ^ t), u) + *p++;
+               C = rotl32((C ^ u), t) + *p++;
+               x = A;
+               A = B;
+               B = C;
+               C = D;
+               D = x;
+       }while(--i);
+       A += *p++;
+       C += *p;
+}
+ 
+void rc6_dec(void* block, rc6_ctx_t *s){
+       uint8_t i;
+       uint32_t t,u,x; /* greetings to Linux? */
+       uint32_t *p;
+       p = &(s->S[2*(s->rounds)+3]);
+       C -= *p--;
+       A -= *p--;
+       
+       i=s->rounds;
+       do{
+               x=D;
+               D=C;
+               C=B;
+               B=A;
+               A=x;
+               u = rotl32(D * (2*D+1), LG_W);
+               t = rotl32(B * (2*B+1), LG_W);
+               C = rotr32(C - *p--, t) ^ u;
+               A = rotr32(A - *p--, u) ^ t;
+       }while(--i);
+       D -= *p--;
+       B -= *p;
+}
+