Add test for equivalent public keys.

This commit is contained in:
akwizgran
2019-05-14 11:32:07 +01:00
parent d2951eb3cd
commit ca591b5c7b

View File

@@ -11,12 +11,14 @@ import org.junit.Test;
import org.whispersystems.curve25519.Curve25519;
import java.security.GeneralSecurityException;
import java.util.Arrays;
import java.util.Random;
import static org.briarproject.bramble.api.keyagreement.KeyAgreementConstants.SHARED_SECRET_LABEL;
import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
import static org.briarproject.bramble.util.StringUtils.fromHexString;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertFalse;
public class KeyAgreementTest extends BrambleTestCase {
@@ -66,11 +68,9 @@ public class KeyAgreementTest extends BrambleTestCase {
@Test
public void testRfc7748TestVector() {
// Private keys need to be clamped because curve25519-java does the
// clamping at key generation time, not multiplication time
byte[] aPriv = AgreementKeyParser.clamp(fromHexString(ALICE_PRIVATE));
byte[] aPriv = parsePrivateKey(ALICE_PRIVATE);
byte[] aPub = fromHexString(ALICE_PUBLIC);
byte[] bPriv = AgreementKeyParser.clamp(fromHexString(BOB_PRIVATE));
byte[] bPriv = parsePrivateKey(BOB_PRIVATE);
byte[] bPub = fromHexString(BOB_PUBLIC);
byte[] sharedSecret = fromHexString(SHARED_SECRET);
Curve25519 curve25519 = Curve25519.getInstance("java");
@@ -79,4 +79,29 @@ public class KeyAgreementTest extends BrambleTestCase {
assertArrayEquals(sharedSecret,
curve25519.calculateAgreement(bPub, aPriv));
}
@Test
public void testDerivesSameSharedSecretFromEquivalentPublicKey() {
byte[] aPub = fromHexString(ALICE_PUBLIC);
byte[] bPriv = parsePrivateKey(BOB_PRIVATE);
byte[] sharedSecret = fromHexString(SHARED_SECRET);
Curve25519 curve25519 = Curve25519.getInstance("java");
// Flip the unused most significant bit of the little-endian public key
byte[] aPubEquivalent = aPub.clone();
aPubEquivalent[31] ^= (byte) 128;
// The public keys should be different but give the same shared secret
assertFalse(Arrays.equals(aPub, aPubEquivalent));
assertArrayEquals(sharedSecret,
curve25519.calculateAgreement(aPub, bPriv));
assertArrayEquals(sharedSecret,
curve25519.calculateAgreement(aPubEquivalent, bPriv));
}
private byte[] parsePrivateKey(String hex) {
// Private keys need to be clamped because curve25519-java does the
// clamping at key generation time, not multiplication time
return AgreementKeyParser.clamp(fromHexString(hex));
}
}