adding RSA-OAEP

[avr-crypto-lib.git] / rsa / rsa_basic.c

diff --git a/rsa/rsa_basic.c b/rsa/rsa_basic.c
new file mode 100644 (file)
index 0000000..b0ef12b
--- /dev/null
+++ b/rsa/rsa_basic.c
@@ -0,0 +1,161 @@
+/* rsa_basic.c */
+/*
+    This file is part of the ARM-Crypto-Lib.
+    Copyright (C) 2006-2011 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/>.
+*/
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include "bigint.h"
+#include "bigint_io.h"
+#include "rsa_basic.h"
+
+#define DEBUG 0
+
+#if DEBUG
+#include "cli.h"
+#endif
+
+void rsa_enc(bigint_t* data, rsa_publickey_t* key){
+/*
+       cli_putstr_P(PSTR("\r\n -->rsa_enc()\r\n m = "));
+       bigint_print_hex(data);
+       cli_putstr_P(PSTR("\r\n e = "));
+       bigint_print_hex(key->exponent);
+       cli_putstr_P(PSTR("\r\n n = "));
+       bigint_print_hex(key->modulus);
+*/
+       bigint_expmod_u(data, data, key->exponent, key->modulus);
+}
+
+/*
+(p,q,dp,dq,qinv)
+m1 = c**dp % p
+m2 = c**dq % q
+h = (m1 - m2) * qinv % p
+m = m2 + q * h
+*/
+
+uint8_t rsa_dec_crt_mono(bigint_t* data, rsa_privatekey_t* key){
+       bigint_t m1, m2;
+       m1.wordv = malloc((key->modulus->length_B + 1) * sizeof(bigint_word_t));
+       m2.wordv = malloc(key->components[1]->length_B * sizeof(bigint_word_t));
+       if(!m1.wordv || !m2.wordv){
+#if DEBUG
+               cli_putstr_P(PSTR("\r\nERROR: OOM! (" __FILE__ ")"));
+#endif
+               free(m1.wordv);
+               free(m2.wordv);
+               return 1;
+       }
+#if DEBUG
+               cli_putstr_P(PSTR("\r\nexp_mod a + b "));
+#endif
+       bigint_expmod_u(&m1, data, key->components[2], key->components[0]);
+       bigint_expmod_u(&m2, data, key->components[3], key->components[1]);
+#if DEBUG
+       cli_putstr_P(PSTR("[done] "));
+#endif
+       bigint_sub_s(&m1, &m1, &m2);
+#if DEBUG
+       cli_putstr_P(PSTR("[done2] "));
+#endif
+       while(BIGINT_NEG_MASK & m1.info){
+#if DEBUG
+               cli_putc(',');
+#endif
+               bigint_add_s(&m1, &m1, key->components[0]);
+       }
+#if DEBUG
+               cli_putstr_P(PSTR("\r\nreduce_mul "));
+#endif
+       bigint_reduce(&m1, key->components[0]);
+       bigint_mul_u(&m1, &m1, key->components[4]);
+#if DEBUG
+               cli_putstr_P(PSTR("[done]"));
+#endif
+       bigint_reduce(&m1, key->components[0]);
+       bigint_mul_u(&m1, &m1, key->components[1]);
+#if DEBUG
+               cli_putstr_P(PSTR(" [done]"));
+#endif
+       bigint_add_u(data, &m1, &m2);
+       free(m1.wordv);
+       free(m2.wordv);
+       return 0;
+}
+
+uint8_t rsa_dec(bigint_t* data, rsa_privatekey_t* key){
+       if(key->n == 1){
+               bigint_expmod_u(data, data, key->components[0], key->modulus);
+               return 0;
+       }
+       if(key->n == 5){
+               if (rsa_dec_crt_mono(data, key)){
+                       return 3;
+               }
+               return 0;
+       }
+       if(key->n<8 || (key->n-5)%3 != 0){
+               return 1;
+       }
+       //rsa_dec_crt_multi(data, key, (key->n-5)/3);
+       return 2;
+}
+
+void rsa_os2ip(bigint_t* dest, const void* data, uint32_t length_B){
+       uint8_t off;
+       off = length_B % sizeof(bigint_word_t);
+       if(!data){
+               if(off){
+                       dest->wordv = realloc(dest->wordv, length_B + sizeof(bigint_word_t) - off);
+                       memmove((uint8_t*)dest->wordv+off, dest->wordv, length_B);
+                       memset(dest->wordv, 0, off);
+               }
+       }else{
+               if(off){
+                       memcpy((uint8_t*)dest->wordv + off, data, length_B);
+                       memset(dest, 0, off);
+               }else{
+                       memcpy(dest->wordv, data, length_B);
+               }
+       }
+       dest->length_B = (length_B + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
+       bigint_changeendianess(dest);
+       bigint_adjust(dest);
+}
+
+void rsa_i2osp(void* dest, bigint_t* src, uint16_t* out_length_B){
+       *out_length_B = bigint_get_first_set_bit(src) / 8 + 1;
+       if(dest){
+               uint16_t i;
+               for(i=*out_length_B; i>0; --i){
+                       *((uint8_t*)dest) = ((uint8_t*)src->wordv)[i-1];
+                       dest = (uint8_t*)dest + 1;
+               }
+       }else{
+               uint8_t off;
+               bigint_changeendianess(src);
+               bigint_adjust(src);
+
+               off = bigint_get_last_set_bit(src)/8;
+               if(off){
+                       memmove(src->wordv, (uint8_t*)src->wordv+off, *out_length_B);
+               }
+       }
+}
+