--- /dev/null
+#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);
+}