uint8_t dsa_verify_message(const dsa_signature_t* s, const void* m, uint16_t m_len_b,
const hfdesc_t* hash_desc, const dsa_ctx_t* ctx) {
bigint_t z;
uint8_t n_B = ctx->domain.q.length_B;
uint8_t hash_value[(hfal_hash_getHashsize(hash_desc)+7)/8];
hfal_hash_mem(hash_desc, hash_value, m, m_len_b);
z.wordv=hash_value;
z.length_B=n_B;
bigint_changeendianess(&z);
bigint_adjust(&z);
return dsa_verify_bigint(s, &z, ctx);
}
void *hash_message(hfdesc_t *hash_function){
uint8_t *block, *hash_value;
uint16_t index = 0;
hfgen_ctx_t ctx;
if(hash_function == NULL){
return NULL;
}
block = malloc(hfal_hash_getBlocksize(hash_function) / 8);
if(block == NULL){
return NULL;
}
hash_value = malloc(hfal_hash_getHashsize(hash_function) / 8);
if(hash_value == NULL){
free(block);
return NULL;
}
hfal_hash_init(hash_function, &ctx);
for(;;){
int a,b;
a = getchar();
if(!isxdigit(a)){
hfal_hash_lastBlock(&ctx, block, index * 8);
break;
}
putchar(a);
b = getchar();
if(!isxdigit(b)){
printf_P(PSTR("*** invalid ***\n"));
hfal_hash_free(&ctx);
free(hash_value);
free(block);
return NULL;
}
putchar(b);
block[index++] = convert_hex_to_byte(a, b);
if(index == hfal_hash_getBlocksize(hash_function) / 8){
hfal_hash_nextBlock(&ctx, block);
}
}
hfal_hash_ctx2hash(hash_value, &ctx);
hfal_hash_free(&ctx);
free(block);
return hash_value;
}
uint8_t rsa_encrypt_oaep(void* dest, uint16_t* out_length,
const void* src, uint16_t length_B,
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);
#if DEBUG
cli_putstr("\r\n buffer_len = ");
cli_hexdump_rev(&buffer_len, 2);
cli_putstr("\r\n modulus_len = ");
cli_hexdump_rev(&key->modulus.length_B, 2);
#endif
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))
% (sizeof(bigint_word_t));
buffer += off;
buffer_len -= 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();
}
}
#if DEBUG
cli_putstr("\r\n msg (raw, pre-feistel):\r\n");
cli_hexdump_block(dest, bigint_length_B(&key->modulus), 4, 16);
#endif
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);
#if DEBUG
cli_putstr("\r\n msg (raw, post-feistel):\r\n");
cli_hexdump_block(dest, bigint_length_B(&key->modulus), 4, 16);
#endif
x.info = 0;
x.length_B = key->modulus.length_B;
x.wordv = dest;
bigint_adjust(&x);
rsa_os2ip(&x, NULL, bigint_length_B(&key->modulus));
#if DEBUG
cli_putstr("\r\ninput-msg (pre enc):\r\n");
cli_hexdump_rev(&src, 2);
cli_hexdump_block(src, length_B, 4, 16);
#endif
rsa_enc(&x, key);
#if DEBUG
cli_putstr("\r\ninput-msg (post enc):\r\n");
cli_hexdump_rev(&src, 2);
cli_hexdump_block(src, length_B, 4, 16);
#endif
rsa_i2osp(NULL, &x, out_length);
return 0;
}
void test_sign2(void){
bigint_word_t d_w[sizeof(ecdsa_test_2_d)];
uint8_t rnd[sizeof(ecdsa_test_2_k)];
uint8_t *hash;
bigint_t d;
const hfdesc_t *hash_desc;
ecc_combi_point_t q;
ecdsa_signature_t sign;
ecdsa_ctx_t ctx;
uint8_t r;
putchar('\n');
d.wordv = d_w;
memcpy_P(rnd, ecdsa_test_2_k, sizeof(ecdsa_test_2_k));
memcpy_P(d_w, ecdsa_test_2_d, sizeof(ecdsa_test_2_d) * sizeof(bigint_word_t));
d.length_W = sizeof(ecdsa_test_2_d) / sizeof(bigint_word_t);
d.info = 0;
bigint_adjust(&d);
hash_desc = &sha224_desc; //hash_select();
hash = malloc(hfal_hash_getHashsize(hash_desc) / 8);
if(hash == NULL){
printf_P(PSTR("DBG: XXX <%S %s %d>\n"), PSTR(__FILE__), __func__, __LINE__);
}
hash_mem_P(hash_desc, hash, ecdsa_test_2_msg, sizeof(ecdsa_test_1_msg) * 8);
printf_P(PSTR("msg hash: "));
cli_hexdump(hash, hfal_hash_getHashsize(hash_desc) / 8);
putchar('\n');
ecc_chudnovsky_point_alloc(&q.chudnovsky, nist_curve_p192_p.length_W * sizeof(bigint_word_t));
ctx.basepoint = &nist_curve_p192_basepoint.chudnovsky;
ctx.priv = &d;
ctx.curve = &nist_curve_p192;
printf("\n d: ");
bigint_print_hex(&d);
printf_P(PSTR("\n Gx: "));
bigint_print_hex(&nist_curve_p192_basepoint.affine.x);
printf_P(PSTR("\n Gy: "));
bigint_print_hex(&nist_curve_p192_basepoint.affine.y);
r = ecc_chudnovsky_multiplication(&q.chudnovsky, &d, &nist_curve_p192_basepoint.chudnovsky, &nist_curve_p192);
if(r){
printf_P(PSTR("ERROR: ecc_chudnovsky_multiplication() returned: %"PRIu8"\n"), r);
}
r = ecc_chudnovsky_to_affine_point(&q.affine, &q.chudnovsky, &nist_curve_p192);
if(r){
printf_P(PSTR("ERROR: ecc_chudnovsky_to_affine_point() returned: %"PRIu8"\n"), r);
}
printf_P(PSTR("\n Qx: "));
bigint_print_hex(&q.affine.x);
printf_P(PSTR("\n Qy: "));
bigint_print_hex(&q.affine.y);
putchar('\n');
ctx.pub = &q.affine;
ecdsa_signature_alloc(&sign, sizeof(ecdsa_test_2_d) * sizeof(bigint_word_t));
r = ecdsa_sign_hash(&sign, hash, hfal_hash_getHashsize(hash_desc) / 8, &ctx, rnd);
if(r){
printf_P(PSTR("ERROR: ecdsa_sign_message() returned: %"PRIu8"\n"), r);
}
printf_P(PSTR(" r: "));
bigint_print_hex(&sign.r);
printf_P(PSTR("\n s: "));
bigint_print_hex(&sign.s);
free(hash);
ecdsa_signature_free(&sign);
ecc_chudnovsky_point_free(&q.chudnovsky);
}
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){
// 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_B = key->modulus.length_B;
x.info = 0;
bigint_adjust(&x);
// cli_putc('b'); uart_flush(0);
rsa_os2ip(&x, NULL, bigint_length_B(&key->modulus));
#if DEBUG
cli_putstr_P(PSTR("\r\n rsa decrypting ..."));
#endif
rsa_dec(&x, key);
#if DEBUG
cli_putstr_P(PSTR(" [done]"));
#endif
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;
}
