public static SignatureTestVector createTestVector2() throws GeneralSecurityException {
    Ed25519PublicKey publicKey =
        Ed25519PublicKey.create(Ed25519Parameters.Variant.CRUNCHY, PUBLIC_KEY_MATERIAL, 0x99887766);
    Ed25519PrivateKey privateKey = Ed25519PrivateKey.create(publicKey, PRIVATE_KEY_MATERIAL);
    return new SignatureTestVector(
        privateKey,
        Hex.decode(
            "0099887766"
                + "3431985050f48157551262d591d0f1f25b9c6808fce4345066cb8216d48fcd9feafa4b24949a7f8c"
                + "abdc16a51030a19d7514c9685c221475bf3cfc363472ee0a"),
        Hex.decode("aa"));
  }
Test utilities for Ed25519. Test vectors are generated by hand for this test.
java_src/src/main/java/com/google/crypto/tink/signature/internal/testing/Ed25519TestUtil.java