Add the ed25519 ref10 code verbatim from supercop-20140622

We might use libsodium or ed25519-donna later on, but for now, let's
see whether this is fast enough.  We should use it in all cases when
performance doesn't matter.

1 files changed, 41 insertions, 0 deletions

diff --git a/src/ext/ed25519/ref10/sign.c b/src/ext/ed25519/ref10/sign.c
new file mode 100644
index 0000000000..de53742a6c
--- /dev/null
+++ b/src/ext/ed25519/ref10/sign.c
@@ -0,0 +1,41 @@
+#include <string.h>
+#include "crypto_sign.h"
+#include "crypto_hash_sha512.h"
+#include "ge.h"
+#include "sc.h"
+
+int crypto_sign(
+  unsigned char *sm,unsigned long long *smlen,
+  const unsigned char *m,unsigned long long mlen,
+  const unsigned char *sk
+)
+{
+  unsigned char pk[32];
+  unsigned char az[64];
+  unsigned char nonce[64];
+  unsigned char hram[64];
+  ge_p3 R;
+
+  memmove(pk,sk + 32,32);
+
+  crypto_hash_sha512(az,sk,32);
+  az[0] &= 248;
+  az[31] &= 63;
+  az[31] |= 64;
+
+  *smlen = mlen + 64;
+  memmove(sm + 64,m,mlen);
+  memmove(sm + 32,az + 32,32);
+  crypto_hash_sha512(nonce,sm + 32,mlen + 32);
+  memmove(sm + 32,pk,32);
+
+  sc_reduce(nonce);
+  ge_scalarmult_base(&R,nonce);
+  ge_p3_tobytes(sm,&R);
+
+  crypto_hash_sha512(hram,sm,mlen + 64);
+  sc_reduce(hram);
+  sc_muladd(sm + 32,hram,az,nonce);
+
+  return 0;
+}