present looks better now (using unverified testvectors)

[avr-crypto-lib.git] / present / present_common.c

diff --git a/present/present_common.c b/present/present_common.c
new file mode 100644 (file)
index 0000000..198c67b
--- /dev/null
+++ b/present/present_common.c
@@ -0,0 +1,104 @@
+/* present_common.c */
+/*
+    This file is part of the AVR-Crypto-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/>.
+*/
+/**
+ * present_common.c
+ * a implementation of the PRESENT block-cipher
+ * author: Daniel Otte
+ * email:  daniel.otte@rub.de
+ * license: GPLv3
+ * 
+ * */
+ 
+#include <string.h>
+#include <stdint.h> 
+#include "memxor.h"
+#include <avr/pgmspace.h>
+
+uint8_t present_sbox(uint8_t b){
+       static const uint8_t sb[] PROGMEM = {
+               0xC, 0x5, 0x6, 0xB,
+               0x9, 0x0, 0xA, 0xD,
+               0x3, 0xE, 0xF, 0x8,
+               0x4, 0x7, 0x1, 0x2
+       };
+       return (pgm_read_byte(&sb[b >> 4]) << 4) | pgm_read_byte(&sb[b & 0xf]);
+}
+
+uint8_t present_sbox_inv(uint8_t b){
+       static const uint8_t sb[] PROGMEM = {
+               0x5, 0xE, 0xF, 0x8,
+               0xC, 0x1, 0x2, 0xD,
+               0xB, 0x4, 0x6, 0x3,
+               0x0, 0x7, 0x9, 0xA
+       };
+       return (pgm_read_byte(&sb[b >> 4]) << 4) | pgm_read_byte(&sb[b & 0xf]);
+}
+
+void present_p(uint8_t* o, uint8_t* i){
+       uint8_t m,n=0,idx=0;
+       for(m=0; m<64; ++m){
+               o[idx] <<= 1;
+               o[idx] |= i[n] >> 7;
+               i[n] <<= 1;
+               idx = (idx + 2) & 7;
+               if((m & 7) == 7){
+                       ++n;
+               }
+               if(m == 31){
+                       idx += 1;
+               }
+       }
+}
+
+
+void present_generic_enc(void* buffer, uint8_t* ctx, uint8_t ksize_B,
+       void(*update)(uint8_t*, uint8_t)){
+       uint8_t i,j,tmp[8], k[ksize_B];
+       memcpy(k, ctx, ksize_B);
+       memxor(buffer, k, 8);
+       for(i=1; i<32; ++i){
+               j = 7;
+               do{
+                       tmp[j] = present_sbox(((uint8_t*)buffer)[j]);
+               }while(j--);
+               present_p(buffer, tmp);
+               update(k, i);
+               memxor(buffer, k, 8);
+       }
+}
+
+void present_generic_dec(void* buffer, uint8_t* ctx, uint8_t ksize_B,
+       void(*update)(uint8_t*, uint8_t)){
+       uint8_t j,tmp[8], k[ksize_B];
+       uint8_t i;
+       memcpy(k, ctx + ksize_B, ksize_B);
+       memxor(buffer, k, 8);
+       i = 31;
+       do{
+               present_p(tmp, buffer);
+               present_p(buffer, tmp);
+               j = 7;
+               do{
+                       ((uint8_t*)buffer)[j] = present_sbox_inv(((uint8_t*)buffer)[j]);
+               }while(j--);
+               update(k, i);
+               memxor(buffer, k, 8);
+       }while(--i);
+}
+