+ RSA-OAEP decryption

[arm-crypto-lib.git] / rsa / rsa_oaep.c

diff --git a/rsa/rsa_oaep.c b/rsa/rsa_oaep.c
index 0a5cf76e2ab4fca2dea3ad009661fe3cad725ace..f39b599fb38f024e867530b3d125a29289853e6e 100644 (file)
--- a/rsa/rsa_oaep.c
+++ b/rsa/rsa_oaep.c
@@ -31,9 +31,6 @@
 
 #include "hfal/hfal_sha1.h"
 
-#include "cli.h"
-#include "uart_lowlevel.h"
-
 mgf1_parameter_t mgf1_default_parameter = {
                &sha1_desc
 };
@@ -73,7 +70,6 @@ uint8_t rsa_encrypt_oaep(void* dest, uint16_t* out_length,
         * */
        off = (sizeof(bigint_word_t) -(bigint_get_first_set_bit(key->modulus)/8+1)%(sizeof(bigint_word_t)*8))
                        % (sizeof(bigint_word_t));
-       uart_flush(0);
        buffer += off;
     buffer_len -= off;
        uint8_t* seed_buffer = buffer + 1;
@@ -88,7 +84,6 @@ uint8_t rsa_encrypt_oaep(void* dest, uint16_t* out_length,
        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);
-       uart_flush(0);
        if(seed){
                memcpy(seed_buffer, seed, hv_len);
        }else{
@@ -102,23 +97,102 @@ uint8_t rsa_encrypt_oaep(void* dest, uint16_t* out_length,
                }
        }
 
-//void mgf1(void* dest, const void* seed, uint16_t seed_len_B, uint16_t out_length_B, const mgf1_parameter_t* p);
-       cli_hexdump_block(dest, buffer_len+off, 4, 8);
        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\ngot to 112\r\n");
-       uart_flush(0);
 
        x.wordv = dest;
        x.length_B = key->modulus->length_B;
        bigint_adjust(&x);
-       cli_putstr("\r\ngot to 118\r\n");
-       uart_flush(0);
 
-       rsa_os2ip(&x, NULL, key->modulus->length_B * sizeof(bigint_word_t));
+       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,
+                             rsa_privatekey_t* key, const rsa_oaep_parameter_t *p,
+                             const rsa_label_t* label, void* seed){
+
+       if(!label){
+               label = &rsa_oaep_default_label;
+       }
+       if(!p){
+               p = &rsa_oaep_default_parameter;
+       }
+       uint8_t *buffer =  dest;
+       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)+7)/8;
+       uint16_t db_len = msg_len - 1 - hv_len;
+       uint8_t maskbuffer[db_len>hv_len?db_len:hv_len];
+
+       uint8_t *seed_buffer = buffer + 1;
+       uint8_t *db_buffer = seed_buffer + hv_len;
+
+       x_len = bigint_length_B(key->modulus);
+       memset(dest, 0, x_len - length_B);
+       buffer = (uint8_t*)dest + x_len - length_B;
+       memcpy(buffer, src, length_B);
+
+       x.wordv = dest;
+       x.length_B = key->modulus->length_B;
+       bigint_adjust(&x);
+
+       rsa_os2ip(&x, NULL, bigint_length_B(key->modulus));
+       rsa_dec(&x, key);
+       rsa_i2osp(NULL, &x, &data_len);
+/*
+       if(data_len != x_len){
+               memmove(buffer + x_len - data_len, buffer, data_len);
+               memset(buffer, 0, x_len - data_len);
+       }
+*/
+       if(data_len > msg_len){
+               return 7;
+       }
+
+       memmove(buffer + msg_len - data_len, buffer, data_len);
+
+       hfal_hash_mem(p->hf, label_hv, label->label, label->length_b);
+/*
+       if(buffer[0] != 0){
+               return 1;
+       }
+*/
+       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)){
+               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;
+}
+
+