--- /dev/null
+
+/* rsa_oaep.c */
+/*
+ This file is part of the ARM-Crypto-Lib.
+ Copyright (C) 2006-2012 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 "memxor.h"
+#include "mgf1.h"
+#include "bigint.h"
+#include "rsa_basic.h"
+#include "rsaes_oaep.h"
+
+#include "random_dummy.h"
+
+#include "hfal/hfal_sha1.h"
+
+#include "cli.h"
+#include "uart_lowlevel.h"
+
+mgf1_parameter_t mgf1_default_parameter = {
+ &sha1_desc
+};
+
+rsa_oaep_parameter_t rsa_oaep_default_parameter = {
+ mgf1,
+ &sha1_desc,
+ &mgf1_default_parameter
+};
+
+rsa_label_t rsa_oaep_default_label = {
+ 0, NULL
+};
+
+uint8_t rsa_encrypt_oaep(void* dest, uint16_t* out_length,
+ const void* src, uint16_t length_B,
+ const rsa_publickey_t* key, const rsa_oaep_parameter_t *p,
+ const rsa_label_t* label, const void* seed){
+
+ if(!p){
+ p = &rsa_oaep_default_parameter;
+ }
+ if(!label){
+ label = &rsa_oaep_default_label;
+ }
+ uint16_t hv_len = (hfal_hash_getHashsize(p->hf)+7)/8;
+ if(length_B > bigint_length_B(&key->modulus) - 2*hv_len - 2){
+ /* message too long */
+ return 1;
+ }
+ uint16_t buffer_len = bigint_length_B(&key->modulus);
+/*
+ cli_putstr("\r\n buffer_len = ");
+ cli_hexdump_rev(&buffer_len, 2);
+ cli_putstr("\r\n modulus_len = ");
+ cli_hexdump_rev(&key->modulus->length_W, 2);
+*/
+ uint8_t* buffer = (uint8_t*)dest;
+ uint8_t off;
+ /* the following needs some explanation:
+ * off is the offset which is used for compensating the effect of
+ * changeendian() when it operates on multi-byte words.
+ * */
+ off = (sizeof(bigint_word_t) -(bigint_get_first_set_bit(&key->modulus)/8+1)%(sizeof(bigint_word_t)*8))
+ % (sizeof(bigint_word_t));
+ buffer += off;
+ buffer_len -= off;
+// cli_putstr("\r\n off = ");
+// cli_hexdump_byte(off);
+ uint8_t* seed_buffer = buffer + 1;
+ uint16_t db_len = buffer_len - hv_len - 1;
+ uint8_t* db = seed_buffer + hv_len;
+ uint16_t maskbuffer_len = db_len>hv_len?db_len:hv_len;
+ uint8_t maskbuffer[maskbuffer_len];
+ bigint_t x;
+
+ memset(dest, 0, seed_buffer - buffer + off);
+ memset(db + hv_len, 0, db_len - hv_len - length_B -1);
+ hfal_hash_mem(p->hf, db, label->label, label->length_b);
+ db[db_len - length_B - 1] = 0x01;
+ memcpy(db+db_len - length_B, src, length_B);
+ if(seed){
+ memcpy(seed_buffer, seed, hv_len);
+ }else{
+ /* generate random seed */
+ if(!prng_get_byte){
+ return 2; /* ERROR: no random generator specified */
+ }
+ uint16_t i;
+ for(i=0; i<hv_len; ++i){
+ seed_buffer[i] = prng_get_byte();
+ }
+ }
+// cli_putstr("\r\n msg (raw, pre-feistel):\r\n");
+// cli_hexdump_block(dest, bigint_length_B(key->modulus), 4, 16);
+ p->mgf(maskbuffer, seed_buffer, hv_len, db_len, p->mgf_parameter);
+ memxor(db, maskbuffer, db_len);
+ p->mgf(maskbuffer, db, db_len, hv_len, p->mgf_parameter);
+ memxor(seed_buffer, maskbuffer, hv_len);
+// cli_putstr("\r\n msg (raw, post-feistel):\r\n");
+// cli_hexdump_block(dest, bigint_length_B(key->modulus), 4, 16);
+
+ x.wordv = dest;
+ bigint_adjust(&x);
+
+ rsa_os2ip(&x, NULL, bigint_length_B(&key->modulus));
+ rsa_enc(&x, key);
+ rsa_i2osp(NULL, &x, out_length);
+ return 0;
+}
+
+uint8_t rsa_decrypt_oaep(void* dest, uint16_t* out_length,
+ const void* src, uint16_t length_B,
+ const rsa_privatekey_t* key, const rsa_oaep_parameter_t *p,
+ const rsa_label_t* label, void* seed){
+
+// cli_putstr("\r\n -->rsa_decrypt_oaep()"); uart_flush(0);
+ if(!label){
+ label = &rsa_oaep_default_label;
+ }
+ if(!p){
+ p = &rsa_oaep_default_parameter;
+ }
+ uint16_t x_len, data_len;
+ bigint_t x;
+ uint16_t hv_len = hfal_hash_getHashsize(p->hf)/8;
+ uint8_t label_hv[hv_len];
+ uint16_t msg_len = bigint_get_first_set_bit(&key->modulus) / 8 + 1;
+ uint16_t db_len = msg_len - hv_len - 1;
+ uint8_t maskbuffer[db_len>hv_len?db_len:hv_len];
+
+ uint8_t *seed_buffer = dest;
+ uint8_t *db_buffer = seed_buffer + hv_len;
+
+ x_len = bigint_get_first_set_bit(&key->modulus)/8;
+ memset(dest, 0, bigint_length_B(&key->modulus) - length_B);
+ memcpy((uint8_t*)dest + bigint_length_B(&key->modulus) - length_B, src, length_B);
+
+// cli_putc('a'); uart_flush(0);
+
+ x.wordv = dest;
+ x.length_W = key->modulus.length_W;
+ x.info = 0;
+ bigint_adjust(&x);
+
+
+// cli_putc('b'); uart_flush(0);
+ rsa_os2ip(&x, NULL, bigint_length_B(&key->modulus));
+// cli_putc('c'); uart_flush(0);
+ rsa_dec(&x, key);
+// cli_putc('d'); uart_flush(0);
+ rsa_i2osp(NULL, &x, &data_len);
+
+// cli_putstr("\r\n msg (raw, pre-move):\r\n");
+// cli_hexdump_block(dest, bigint_length_B(key->modulus), 4, 16);
+
+ if(data_len > x_len){
+ return 7;
+ }
+/*
+ cli_putstr("\r\n moving some bytes; x_len = ");
+ cli_hexdump_rev(&x_len, 2);
+ cli_putstr(" data_len = ");
+ cli_hexdump_rev(&data_len, 2);
+ uart_flush(0);
+*/
+ if(x_len != data_len){
+ memmove((uint8_t*)dest + x_len - data_len, dest, data_len);
+// cli_putstr(" (oh, not dead yet?!)");
+// uart_flush(0);
+ memset(dest, 0, x_len - data_len);
+ }
+
+ hfal_hash_mem(p->hf, label_hv, label->label, label->length_b);
+/*
+ cli_putstr("\r\n msg (raw, pre-feistel):\r\n");
+ cli_hexdump_block(seed_buffer, bigint_length_B(key->modulus), 4, 16);
+ uart_flush(0);
+*/
+ p->mgf(maskbuffer, db_buffer, db_len, hv_len, p->mgf_parameter);
+ memxor(seed_buffer, maskbuffer, hv_len);
+ p->mgf(maskbuffer, seed_buffer, hv_len, db_len, p->mgf_parameter);
+ memxor(db_buffer, maskbuffer, db_len);
+
+ if(memcmp(label_hv, db_buffer, hv_len)){
+// cli_putstr("\r\nDBG: DB:\r\n");
+// cli_hexdump_block(db_buffer, db_len, 4, 16);
+ return 2;
+ }
+
+ uint16_t ps_len=0;
+ while(db_buffer[hv_len + ps_len++] == 0)
+ ;
+
+ --ps_len;
+ if(db_buffer[hv_len + ps_len] != 1){
+ return 3;
+ }
+
+ if(seed){
+ memcpy(seed, seed_buffer, hv_len);
+ }
+
+ msg_len = db_len - hv_len - 1 - ps_len;
+ memmove(dest, db_buffer + hv_len + ps_len + 1, msg_len);
+
+ *out_length = msg_len;
+
+ return 0;
+}
+
+
projects / arm-crypto-lib.git / blobdiff