// -3d1d 6db7 8251 f371 * -7a18 3791 d18b b7c5 = 1d25ce4fdf93390f8d6c709f4d711cf5
// -20538248dece6d29068d * 400b1411b874f81394c6 = -81646b193d95136a6fedb73cee6d30c39fb950e
// -BC8B 7D53 4921 853D * 0DDA 6044 00CE DDE6 = -a33eb0c5847db8837589c22db395dce
void test_mul_simple(void){
bigint_t a, b, c;
// uint8_t a_b[10] = {0x8d, 0x06, 0x29, 0x6d, 0xce, 0xde, 0x48, 0x82, 0x53, 0x20};
// uint8_t b_b[10] = {0xc6, 0x94, 0x13, 0xf8, 0x74, 0xb8, 0x11, 0x14, 0x0b, 0x40};
uint8_t a_b[8] = {0x3d, 0x85, 0x21, 0x49, 0x53, 0x7d, 0x8b, 0xbc};
uint8_t b_b[8] = {0xe6, 0xdd, 0xce, 0x00, 0x44, 0x60, 0xda, 0x0d};
uint8_t c_b[16];
a.wordv=a_b;
b.wordv=b_b;
c.wordv=c_b;
a.length_B = 8;
b.length_B = 8;
a.info=0x80;
bigint_adjust(&a);
bigint_adjust(&b);
bigint_mul_s(&c, &a, &b);
cli_putstr_P(PSTR("\r\n test: "));
bigint_print_hex(&a);
cli_putstr_P(PSTR(" * "));
bigint_print_hex(&b);
cli_putstr_P(PSTR(" = "));
bigint_print_hex(&c);
}
void test_gcdext_simple(void){
bigint_t a, b, c, d, e;
uint8_t a_b[5] = {0x71, 0x07, 0x00, 0x09, 0x16};
uint8_t b_b[5] = {0x72, 0x7D, 0x57, 0xAC, 0X6F};
uint8_t c_b[6], d_b[6], e_b[6];
a.wordv=a_b;
a.length_B = 5;
a.info=0x00;
bigint_adjust(&a);
b.wordv=b_b;
b.length_B = 5;
b.info=0x00;
bigint_adjust(&b);
c.wordv = c_b;
d.wordv = d_b;
e.wordv = e_b;
bigint_gcdext(&c, &d, &e, &a, &b);
cli_putstr_P(PSTR("\r\n test: gcd( "));
bigint_print_hex(&a);
cli_putstr_P(PSTR(", "));
bigint_print_hex(&b);
cli_putstr_P(PSTR(") => a = "));
bigint_print_hex(&d);
cli_putstr_P(PSTR("; b = "));
bigint_print_hex(&e);
cli_putstr_P(PSTR("; gcd = "));
bigint_print_hex(&c);
}
void load_rsa_key_blob(rsa_ctx_t* ctx){
if(ctx->modulus.wordv){
free(ctx->modulus.wordv);
}
ctx->modulus.wordv = malloc(ALL_LEN_B);
if(ctx->modulus.wordv==NULL){
cli_putstr_P(PSTR("\r\nERROR: OUT OF MEMORY!!!"));
return;
}
ctx->modulus.info = ctx->privexp.info = ctx->pubexp.info = 0;
memcpy_P(ctx->modulus.wordv, rsa_key_blob, ALL_LEN_B);
ctx->modulus.length_B=N_LEN_B;
ctx->pubexp.wordv = ctx->modulus.wordv+N_LEN_B;
ctx->pubexp.length_B = E_LEN_B;
ctx->privexp.wordv = ctx->pubexp.wordv+E_LEN_B;
ctx->privexp.length_B = D_LEN_B;
bigint_changeendianess(&(ctx->modulus));
bigint_changeendianess(&(ctx->pubexp));
bigint_changeendianess(&(ctx->privexp));
bigint_adjust(&(ctx->modulus));
bigint_adjust(&(ctx->pubexp));
bigint_adjust(&(ctx->privexp));
}
void testrun_performance_multiply_bigint(void){
printf_P(PSTR("\n=== performance measurement (invert) ===\n"));
unsigned i,j;
uint64_t time_a = 0, time_b = 0;
uint32_t tmp;
bigint_t a, b, v;
bigint_word_t v_w[192 * 2 / BIGINT_WORD_SIZE];
bigint_word_t a_w[192 / BIGINT_WORD_SIZE];
bigint_word_t b_w[192 / BIGINT_WORD_SIZE];
a.wordv = a_w;
b.wordv = b_w;
v.wordv = v_w;
for(j = 0; j < 32; ++j){
for(i = 0; i < 192 / BIGINT_WORD_SIZE; ++i){
((uint8_t*)a_w)[i] = random();
}
a.length_W = 192 / BIGINT_WORD_SIZE;
a.info = 0;
bigint_adjust(&a);
for(i = 0; i < 192 / BIGINT_WORD_SIZE; ++i){
((uint8_t*)b_w)[i] = random();
}
b.length_W = 192 / BIGINT_WORD_SIZE;
b.info = 0;
bigint_adjust(&b);
for(i = 0; i < 16; ++i){
startTimer(1);
START_TIMER;
bigint_mul_u(&v,&a, &b);
STOP_TIMER;
tmp = stopTimer();
time_a += tmp;
time_b += tmp;
START_TIMER;
bigint_reduce_p192(&v);
STOP_TIMER;
tmp = stopTimer();
time_b += tmp;
}
}
time_a >>= 8;
++time_a;
time_a >>= 1;
time_b >>= 8;
++time_b;
time_b >>= 1;
printf_P(PSTR(" multiply costs %7"PRIu32" cycles\n"), (uint32_t)time_a);
printf_P(PSTR(" multiply + reduce costs %7"PRIu32" cycles\n"), (uint32_t)time_b);
}
void testrun_performance_invert_bigint(void){
printf_P(PSTR("\n=== performance measurement (invert) ===\n"));
unsigned i,j;
uint64_t time = 0;
bigint_t a, v;
bigint_word_t v_w[192 / BIGINT_WORD_SIZE];
bigint_word_t a_w[192 / BIGINT_WORD_SIZE];
a.wordv = a_w;
v.wordv = v_w;
for(j = 0; j < 32; ++j){
for(i = 0; i < 192 / BIGINT_WORD_SIZE; ++i){
((uint8_t*)v_w)[i] = random();
}
v.length_W = 192 / BIGINT_WORD_SIZE;
v.info = 0;
bigint_adjust(&v);
for(i = 0; i < 16; ++i){
startTimer(1);
START_TIMER;
bigint_inverse(&a, &v, &nist_curve_p192_p);
STOP_TIMER;
time += stopTimer();
}
}
time >>= 8;
++time;
time >>= 1;
printf_P(PSTR(" invert costs %"PRIu32" cycles\n"), (uint32_t)time);
}
uint8_t read_bigint(bigint_t *a, char *prompt){
uint16_t read_length, actual_length;
uint8_t off;
uint8_t *buffer;
char read_int_str[18];
cli_putstr(prompt);
cli_putstr_P(PSTR("\r\n length: "));
cli_getsn(read_int_str, 16);
read_length = own_atou(read_int_str);
off = (sizeof(bigint_word_t) - (read_length % sizeof(bigint_word_t))) % sizeof(bigint_word_t);
buffer = malloc(((read_length + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t)) * sizeof(bigint_word_t));
if(!buffer){
cli_putstr_P(PSTR("\r\nERROR: OOM!"));
return 2;
}
cli_putstr_P(PSTR("\r\n data: "));
memset(buffer, 0, sizeof(bigint_word_t));
actual_length = read_os(buffer + off, read_length, NULL);
if(actual_length != read_length){
cli_putstr_P(PSTR("\r\nERROR: unexpected end of data!"));
free(buffer);
return 1;
}
a->wordv = (bigint_word_t*)buffer;
a->length_W = (read_length + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
a->info = 0;
bigint_changeendianess(a);
bigint_adjust(a);
return 0;
}
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);
}
uint8_t load_bigint_from_os(bigint_t *a, PGM_VOID_P os, uint16_t length_B){
a->length_W = BIGINT_CEIL(length_B) / sizeof(bigint_word_t);
a->wordv = malloc(BIGINT_CEIL(length_B));
if(!a->wordv){
cli_putstr_P(PSTR("\r\nOOM!\r\n"));
return 1;
}
memset(a->wordv, 0, sizeof(bigint_word_t));
memcpy_P((uint8_t*)a->wordv + BIGINT_OFF(length_B), os, length_B);
a->info = 0;
bigint_changeendianess(a);
bigint_adjust(a);
return 0;
}
// [fail (c)]: A862 % 2752 = 0D1A ; should a862 % 2752 = b1a
void test_reduce_simple(void){
bigint_t a, b, c;
uint8_t a_b[2] = {0x62, 0xA8};
uint8_t b_b[2] = {0x52, 0x27};
uint8_t c_b[2];
a.wordv=a_b;
a.length_B = 2;
a.info=0x00;
bigint_adjust(&a);
b.wordv=b_b;
b.length_B = 2;
b.info=0x00;
bigint_adjust(&b);
c.wordv = c_b;
bigint_copy(&c, &a);
bigint_reduce(&c, &b);
cli_putstr_P(PSTR("\r\n test: "));
bigint_print_hex(&a);
cli_putstr_P(PSTR(" % "));
bigint_print_hex(&b);
cli_putstr_P(PSTR(" = "));
bigint_print_hex(&c);
}
void test_square_simple(void){
bigint_t a, c;
uint8_t a_b[11] = {0xe6, 0x70, 0x7d, 0x43, 0x74, 0x07, 0x20, 0x22, 0x6a, 0xb8, 0xf4};
uint8_t c_b[22];
a.wordv=a_b;
c.wordv=c_b;
a.length_B = 11;
a.info=0x00;
bigint_adjust(&a);
bigint_square(&c, &a);
cli_putstr_P(PSTR("\r\n test: "));
bigint_print_hex(&a);
cli_putstr_P(PSTR("**2 = "));
bigint_print_hex(&c);
}
uint8_t bigint_read_hex_echo(bigint_t *a) {
uint16_t allocated = 0;
uint8_t shift4 = 0;
uint16_t t, idx = 0;
a->length_W = 0;
a->wordv = NULL;
a->info = 0;
for (;;) {
if (allocated - idx < 1) {
bigint_word_t *p;
p = realloc(a->wordv, allocated += BLOCKSIZE);
if (p == NULL) {
cli_putstr("\r\nERROR: Out of memory!");
free(a->wordv);
return 0xff;
}
memset((uint8_t*)p + allocated - BLOCKSIZE, 0, BLOCKSIZE);
a->wordv = p;
}
t = read_byte();
if (idx == 0) {
if (t & 0x0400) {
/* got minus */
a->info |= BIGINT_NEG_MASK;
continue;
} else {
if (t == 0x0100) {
free(a->wordv);
a->wordv = NULL;
return 1;
}
}
}
if (t <= 0x00ff) {
((uint8_t*)(a->wordv))[idx++] = (uint8_t)t;
} else {
if (t & 0x0200) {
shift4 = 1;
((uint8_t*)(a->wordv))[idx++] = (uint8_t)((t & 0x0f) << 4);
}
break;
}
}
/* we have to reverse the byte array */
uint8_t tmp;
uint8_t *p, *q;
a->length_W = (idx + sizeof(bigint_word_t) - 1) / sizeof(bigint_word_t);
p = (uint8_t*)(a->wordv);
q = (uint8_t*)a->wordv + a->length_W * sizeof(bigint_word_t) - 1;
while (q > p) {
tmp = *p;
*p = *q;
*q = tmp;
p++; q--;
}
bigint_adjust(a);
if (shift4) {
bigint_shiftright(a, 4);
}
if(a->length_W == 1 && a->wordv[0] == 0){
a->length_W = 0;
a->info = 0;
}
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);
}
void testrun_performance_reduce_bigint(void){
printf_P(PSTR("\n=== performance measurement (reduce) ===\n"));
unsigned i, j;
bigint_t a,b,v;
bigint_word_t v_w[192 * 2 / BIGINT_WORD_SIZE];
bigint_word_t a_w[192 * 2 / BIGINT_WORD_SIZE];
bigint_word_t b_w[192 * 2 / BIGINT_WORD_SIZE];
uint32_t time_a, time_b;
int32_t time_diff;
int16_t faster_percent;
v.wordv = v_w;
for(j = 0; j < 32; ++j){
do{
for(i = 0; i < 192 * 2 / BIGINT_WORD_SIZE; ++i){
((uint8_t*)v_w)[i] = random();
}
v.length_W = 192 * 2 / BIGINT_WORD_SIZE;
v.info = 0;
bigint_adjust(&v);
}while(0);
// printf_P(PSTR("candidate:\n"));
// bigint_print_hex(&v);
a.wordv = a_w;
b.wordv = b_w;
calibrateTimer();
// printf_P(PSTR("\n going to test optimized version: ...\n"));
uart0_flush();
time_a = 0;
for(i = 0; i < 16; ++i){
bigint_copy(&a, &v);
startTimer(1);
START_TIMER;
bigint_reduce_p192(&a);
STOP_TIMER;
time_a += stopTimer();
}
// printf_P(PSTR(" took: %"PRIu32" cycles\nresult:"), time);
// bigint_print_hex(&a);
// printf_P(PSTR("\n going to test not-optimized version: ...\n"));
// uart0_flush();
time_b = 0;
for(i = 0; i < 16; ++i){
bigint_copy(&b, &v);
startTimer(1);
START_TIMER;
bigint_reduce(&b, &nist_curve_p192_p);
STOP_TIMER;
time_b += stopTimer();
}
// printf_P(PSTR(" took: %"PRIu32" cycles\nresult:"), time);
// bigint_print_hex(&b);
time_diff = time_b - time_a;
faster_percent = (time_diff * 100) / time_b;
printf_P(PSTR(" delta: %7"PRId32" (%3"PRId16"%%) :-"), time_diff, faster_percent);
if(bigint_cmp_u(&a, &b)){
printf_P(PSTR("(\n"));
} else {
printf_P(PSTR(")\n"));
}
uart0_flush();
}
}
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;
}
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;
}
