serval-dna/crypto.c

49 lines
1.6 KiB
C

/*
Serval DNA internal cryptographic operations
Copyright 2013 Serval Project Inc.
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 2
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, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "serval.h"
#include "overlay_address.h"
#include "crypto.h"
#include "keyring.h"
// 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, size_t *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);
if (crypto_sign_verify_detached(&message[*message_len], hash, crypto_hash_sha512_BYTES, subscriber->sas_public))
return WHY("Signature verification failed");
return 0;
}