public static SignatureTestVector createTestVector3() throws GeneralSecurityException {
    Ed25519PublicKey publicKey =
        Ed25519PublicKey.create(Ed25519Parameters.Variant.LEGACY, PUBLIC_KEY_MATERIAL, 0x99887766);
    Ed25519PrivateKey privateKey = Ed25519PrivateKey.create(publicKey, PRIVATE_KEY_MATERIAL);
    return new SignatureTestVector(
        privateKey,
        Hex.decode(
            "0099887766"
                + "e828586415b1226c118617a2b56b923b6717e83c4d265fcb4e2cdf3cb902ce7b9b1ecd840"
                + "5cb4e6a8e248ef5478891b5b6f80f737df16594f88662595d8f140e"),
        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