Use Ed25519 keys.

[tinc] / src / ed25519 / sign.c

diff --git a/src/ed25519/sign.c b/src/ed25519/sign.c
new file mode 100644 (file)
index 0000000..199a839
--- /dev/null
+++ b/src/ed25519/sign.c
@@ -0,0 +1,31 @@
+#include "ed25519.h"
+#include "sha512.h"
+#include "ge.h"
+#include "sc.h"
+
+
+void ed25519_sign(unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key, const unsigned char *private_key) {
+    sha512_context hash;
+    unsigned char hram[64];
+    unsigned char r[64];
+    ge_p3 R;
+
+
+    sha512_init(&hash);
+    sha512_update(&hash, private_key + 32, 32);
+    sha512_update(&hash, message, message_len);
+    sha512_final(&hash, r);
+
+    sc_reduce(r);
+    ge_scalarmult_base(&R, r);
+    ge_p3_tobytes(signature, &R);
+
+    sha512_init(&hash);
+    sha512_update(&hash, signature, 32);
+    sha512_update(&hash, public_key, 32);
+    sha512_update(&hash, message, message_len);
+    sha512_final(&hash, hram);
+
+    sc_reduce(hram);
+    sc_muladd(signature + 32, hram, private_key, r);
+}