ed25519/sign.c

   1 #include "ed25519.h"
   2 #include "sha512.h"
   3 #include "ge.h"
   4 #include "sc.h"
   5
   6
   7 void ed25519_sign(unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key, const unsigned char *private_key) {
   8     sha512_context hash;
   9     unsigned char hram[64];
  10     unsigned char r[64];
  11     ge_p3 R;
  12
  13
  14     sha512_init(&hash);
  15     sha512_update(&hash, private_key + 32, 32);
  16     sha512_update(&hash, message, message_len);
  17     sha512_final(&hash, r);
  18
  19     sc_reduce(r);
  20     ge_scalarmult_base(&R, r);
  21     ge_p3_tobytes(signature, &R);
  22
  23     sha512_init(&hash);
  24     sha512_update(&hash, signature, 32);
  25     sha512_update(&hash, public_key, 32);
  26     sha512_update(&hash, message, message_len);
  27     sha512_final(&hash, hram);
  28
  29     sc_reduce(hram);
  30     sc_muladd(signature + 32, hram, private_key, r);
  31 }