added signature support (doesn't work yet)

libpcp/ed.c

@@ -0,0 +1,86 @@
+/*
+    This file is part of Pretty Curved Privacy (pcp1).
+
+    Copyright (C) 2013 T.Linden.
+
+    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 3 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, see <http://www.gnu.org/licenses/>.
+
+    You can contact me by mail: <tlinden AT cpan DOT org>.
+*/
+
+#include "ed.h"
+
+int pcp_ed_verify(unsigned char *input, size_t inputlen, pcp_sig_t *sig, pcp_pubkey_t *p) {
+  
+  unsigned char *hash = ucmalloc(crypto_hash_sha256_BYTES + crypto_sign_BYTES); // from sig
+  unsigned char *check = ucmalloc(crypto_hash_sha256_BYTES); // from file
+  size_t mlen = 0;
+
+  if(crypto_sign_open(hash, &mlen, sig->edsig, crypto_hash_sha256_BYTES + crypto_sign_BYTES, p->public) != 0) {
+    fatal("Failed to open the signature using the public key 0x%s!\n", p->id);
+    goto errve1;
+  }
+
+  crypto_hash_sha256(check, input, inputlen);
+
+  if(memcmp(check, hash, crypto_hash_sha256_BYTES) != 0) {
+    fatal("Failed to verify the signature, hashes differ!\n");
+    goto errve1;
+  }
+
+  free(hash);
+  free(check);
+  return 0;
+
+ errve1:
+  free(hash);
+  free(check);
+  return 1;
+}
+
+pcp_sig_t *pcp_ed_sign(unsigned char *message, size_t messagesize, pcp_key_t *s) {
+  unsigned char *hash = ucmalloc(crypto_hash_sha256_BYTES);
+  size_t slen = crypto_hash_sha256_BYTES + crypto_sign_BYTES;
+  unsigned char *signature = ucmalloc(slen);
+
+  crypto_hash_sha256(hash, message, messagesize);
+
+  crypto_sign(signature, &slen, hash, crypto_hash_sha256_BYTES, s->secret);
+
+  pcp_sig_t *sig = pcp_ed_newsig(signature, s->id);
+
+  return sig;
+}
+
+pcp_sig_t *pcp_ed_newsig(unsigned char *hash, char *id) {
+  pcp_sig_t *sig = ucmalloc(sizeof(pcp_sig_t));
+  sig->version = PCP_SIG_VERSION;
+  sig->ctime = (long)time(0);
+  memcpy(sig->edsig, hash, crypto_hash_sha256_BYTES + crypto_sign_BYTES);
+  memcpy(sig->id, id, 17);
+  return sig;
+}
+
+pcp_sig_t *sig2native(pcp_sig_t *s) {
+  s->version = be32toh(s->version);
+  s->ctime   = be64toh(s->ctime);
+  return s;
+}
+
+pcp_sig_t *sig2be(pcp_sig_t *s) {
+  s->version = htobe32(s->version);
+  s->ctime   = htobe64(s->ctime);
+  return s;
+}
+