Java Crypto - Sign and Verify Failure

[Ron McLeod]

I am attempting to sign and then verify a message using a secp256r1 key pair, but I am getting an exception during the verify operation.  I have a feeling that it may be related to the particular curve that I am using.

Any clues where I can look to troubleshoot this problem?

public class CryptoServiceTest {
	private static final byte[] message = ByteUtilities.toByteArray("0123456789ABCDEF0011223344");

	@ConfigProperty(name = "pki.smdp.auth.pkcs12.name")
	String authKeystoreName;

	@ConfigProperty(name = "pki.smdp.auth.pkcs12.pass")
	String authKeystorePassword;

	@ConfigProperty(name = "pki.smdp.auth.pkcs12.alias")
	String authKeystoreAlias;

	@Test
	public void signAndVerifyPoc() throws NoSuchAlgorithmException, InvalidKeyException, 
			SignatureException, UnrecoverableEntryException, 
			KeyStoreException, CertificateException, IOException {
			
		KeyStore dpauthKeystore = KeyStore.getInstance("PKCS12");
		InputStream fis = KeyStoreManager.class.getResourceAsStream(authKeystoreName);
		dpauthKeystore.load(fis, authKeystorePassword.toCharArray());

		// certificate
		Certificate authCertificate = dpauthKeystore.getCertificate(authKeystoreAlias);

		// public key
		ECPublicKey authPublicKey = (ECPublicKey) authCertificate.getPublicKey();

		// private key
		KeyStore.ProtectionParameter protParam = 
			new KeyStore.PasswordProtection(authKeystorePassword.toCharArray());
		KeyStore.PrivateKeyEntry privateKeyEntry = 
			(KeyStore.PrivateKeyEntry) (dpauthKeystore.getEntry(authKeystoreAlias, protParam));
		ECPrivateKey authPrivateKey = (ECPrivateKey) privateKeyEntry.getPrivateKey();

		// algorithm - should be derived from certificate
		String algorithm = "SHA256withECDSA";

		// sign
		Signature signSig = Signature.getInstance(algorithm);
		signSig.initSign(authPrivateKey);
		signSig.update(message);
		byte[] messageSignature = signSig.sign();
		System.out.println("Signature: " + ByteUtilities.toHexString(messageSignature));

		// verify
		Signature verifySig = Signature.getInstance(algorithm);
		verifySig.initVerify(authPublicKey);
		verifySig.update(message);
		boolean ok = verifySig.verify(message);  // ** exception thrown here **
		System.out.println("Verification OK?: " + ok);
	}
}

Signature: 3045022100A4568657332BE0BA59753BA31DE68C14F7E134E622   1C4D96671538F3AA43F1D402204CA288BC7BF85BCDC611A6708B   FB61DB875954E013B2E4B5ABB849021E393218 java.security.SignatureException: Could not verify signature Caused by: java.security.SignatureException: Invalid encoding for signature Caused by: java.io.IOException: Sequence tag error

[Ron McLeod]

Doh - I was trying to verify against the message itself and not the signature

The message Invalid encoding for signature should have been enough of a clue.


This:

boolean ok = verifySig.verify(message);

should be:

boolean ok = verifySig.verify(messageSignature);

[Stephan van Hulst]

One other thing: There is a reason that KeyStore.load() accepts the password as a char[] and not as a String. After you've loaded the key store, you should clear the password.

You're using Quarkus right? Instead of injecting the password using @ConfigProperty, try if this works:

char[] authKeystorePassword = ConfigProvider.getConfig().getValue("pki.smdp.auth.pkcs12.pass", char[].class);

try {
  dpauthKeystore.load(fis, authKeystorePassword);
}

finally {
  Arrays.fill(authKeystorePassword, (char) 0);
}

If this doesn't work it's no disaster, because presumably you're running this code on a protected server (where the password is available in a configuration file anyway).