int cmd_serval_verify(const char *sas_key,
const size_t sas_key_len,
const unsigned char *msg,
const size_t msg_len,
const char *sig,
const size_t sig_len) {
int verdict = 0;
unsigned char bin_sig[SIGNATURE_BYTES];
unsigned char bin_sas[SAS_SIZE];
CHECK_ERR(sig_len == 2*SIGNATURE_BYTES,"Invalid signature");
CHECK_ERR(sas_key_len == 2*SAS_SIZE,"Invalid SAS key");
// convert signature from hex to binary
CHECK_ERR(fromhexstr(bin_sig,sig,SIGNATURE_BYTES) == 0,"Invalid signature");
CHECK_ERR(fromhexstr(bin_sas,sas_key,SAS_SIZE) == 0,"Invalid SAS key");
DEBUG("Message to verify:\n%s",msg);
unsigned char hash[crypto_hash_sha512_BYTES];
crypto_hash_sha512(hash,msg,msg_len);
if (crypto_verify_signature(bin_sas, hash, crypto_hash_sha512_BYTES,
&bin_sig[0], SIGNATURE_BYTES) == 0)
verdict = 1; // successfully verified
error:
return verdict;
}
// verify the signature at the end of a message, on return message_len will be reduced by the length of the signature.
int crypto_verify_message(struct subscriber *subscriber, unsigned char *message, int *message_len)
{
if (!subscriber->sas_valid){
keyring_send_sas_request(subscriber);
return WHY("SAS key not currently on record, cannot verify");
}
if (*message_len < SIGNATURE_BYTES)
return WHY("Message is too short to include a signature");
*message_len -= SIGNATURE_BYTES;
unsigned char hash[crypto_hash_sha512_BYTES];
crypto_hash_sha512(hash,message,*message_len);
return crypto_verify_signature(subscriber->sas_public, hash,
crypto_hash_sha512_BYTES, &message[*message_len], SIGNATURE_BYTES);
}
int
cmd_serval_verify(svl_crypto_ctx *ctx)
{
int verdict = 0;
CHECK_ERR(ctx && ctx->msg && ctx->signature[0] && ctx->sas_public[0],"Invalid ctx");
DEBUG("Message to verify:\n%s", ctx->msg);
unsigned char hash[crypto_hash_sha512_BYTES];
crypto_hash_sha512(hash, ctx->msg, ctx->msg_len);
int sig_ret = crypto_verify_signature(ctx->sas_public,
hash,
crypto_hash_sha512_BYTES,
ctx->signature,
SIGNATURE_BYTES);
if (sig_ret == 0)
verdict = 1; // successfully verified
error:
return verdict;
}
