Ed25519 Sign Verification using libsodium

ed25519-verify.c

#include "sodium.h"

int main(void)
{
  sodium_init();
  crypto_sign_state st;

  unsigned char sig[64];

  unsigned long long siglen;

  // Signature, message and Public Key from RFC-8037
  char sig_hex[129] = "\x63\xc3\x0c\xe0\x78\xf0\xc8\x4d\xc5\x9a\x52\x49\xd1\x4f\x37\xd1\xad\xb3\x45\x17\x0f\x1a\x04\xcd\x96\x67\x72\xf5\xee\x79\x32\x63\x1b\x8f\xb1\xb5\x2c\x2b\x9b\xee\x3a\x3c\x2f\x12\x02\xba\xf2\x69\x79\x55\x32\x36\x34\xb3\x3e\x68\x7f\x2e\x45\x2b\xf4\xe1\x17\x07";
  const char *m = "\xb6\x33\x37\xd1\xea\x4c\xf5\x3b\xd0\xa8\x07\x56\x36\x19\x2c\x1e\x40\x09\x8f\x01\x13\xa8\xd1\xfc\xed\xd2\x97\x1e\xb9\x34\x0d\x28";
  const unsigned char pk[32] = "\x23\x65\xfb\x69\x44\x94\xf1\x20\x97\xb9\x52\x47\xdc\x89\x01\x6b\x63\x70\xf1\xc4\xdd\x3a\xe1\xd8\xd6\x31\x3b\x98\x9b\x4f\x5d\x2c";
  unsigned long long mlen = 32;

  crypto_sign_ed25519ph_init(&st);
  crypto_sign_ed25519ph_update(&st, (const unsigned char *)m, mlen);

  int verified = crypto_sign_ed25519ph_final_verify(&st, sig_hex, pk);
  printf("Signature verified: %d\n", verified);
}

gcc test.c -lsodium -o test.o
./test.o