X-Git-Url: https://git.cryptolib.org/?p=arm-crypto-lib.git;a=blobdiff_plain;f=rc6%2Frc6.c;fp=rc6%2Frc6.c;h=920c9475a1a65e02585d0388e5fd29244ce32abf;hp=0000000000000000000000000000000000000000;hb=3fdf0954404224cef94db2086348b3fa6020aaa4;hpb=4f19c43af8afeb3c569eb7b4aa15907832cf8e5c

diff --git a/rc6/rc6.c b/rc6/rc6.c
new file mode 100644
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--- /dev/null
+++ b/rc6/rc6.c
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+/* 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;
+}
+