Test X25519 key exchange
Test that X25519 key agreement works with Keystore-backed keys.
This is tested by generating two X25519 key pairs, using the private
key from each with the public key of the other for key agreement, and
comparing the secrets.
Bug: 194359292
Test: atest android.keystore.cts.Curve25519Test
Change-Id: I42ee0297fbca9b2bc430647070b44639b4179489
diff --git a/tests/tests/keystore/src/android/keystore/cts/Curve25519Test.java b/tests/tests/keystore/src/android/keystore/cts/Curve25519Test.java
index 95d0d0c..8a37b16 100644
--- a/tests/tests/keystore/src/android/keystore/cts/Curve25519Test.java
+++ b/tests/tests/keystore/src/android/keystore/cts/Curve25519Test.java
@@ -37,14 +37,17 @@
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
-import java.security.ProviderException;
import java.security.Signature;
import java.security.SignatureException;
import java.security.interfaces.EdECPublicKey;
import java.security.spec.ECGenParameterSpec;
+import java.security.spec.InvalidKeySpecException;
import java.security.spec.NamedParameterSpec;
+import java.util.Arrays;
import java.util.Base64;
+import javax.crypto.KeyAgreement;
+
@RunWith(AndroidJUnit4.class)
public class Curve25519Test {
private void deleteEntry(String entry) {
@@ -58,23 +61,44 @@
@Test
public void x25519KeyAgreementTest() throws NoSuchAlgorithmException, NoSuchProviderException,
- InvalidAlgorithmParameterException {
+ InvalidAlgorithmParameterException, InvalidKeySpecException, InvalidKeyException {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("EC", "AndroidKeyStore");
- final String alias = "x25519-alias";
- deleteEntry(alias);
+ // Aliases for both keys.
+ final String firstKeyAlias = "x25519-alias";
+ deleteEntry(firstKeyAlias);
+ final String secondKeyAlias = "x25519-alias-second";
+ deleteEntry(secondKeyAlias);
- KeyGenParameterSpec keySpec = new KeyGenParameterSpec.Builder(alias,
- KeyProperties.PURPOSE_AGREE_KEY)
+ // Generate first x25519 key pair.
+ KeyGenParameterSpec firstKeySpec = new KeyGenParameterSpec.Builder(firstKeyAlias,
+ KeyProperties.PURPOSE_AGREE_KEY)
.setAlgorithmParameterSpec(new ECGenParameterSpec("x25519")).build();
- kpg.initialize(keySpec);
+ kpg.initialize(firstKeySpec);
+ KeyPair firstKeyPair = kpg.generateKeyPair();
- //TODO(b/214203951): Remove this try/catch once Conscrypt class are available.
- try {
- kpg.generateKeyPair();
- fail("Should not be supported yet");
- } catch (ProviderException e) {
- assertThat(e.getMessage()).isEqualTo("Curve XDH not supported yet");
- }
+ // Generate second x25519 key pair.
+ KeyGenParameterSpec secondKeySpec = new KeyGenParameterSpec.Builder(secondKeyAlias,
+ KeyProperties.PURPOSE_AGREE_KEY)
+ .setAlgorithmParameterSpec(new ECGenParameterSpec("x25519")).build();
+ kpg.initialize(secondKeySpec);
+ KeyPair secondKeyPair = kpg.generateKeyPair();
+
+ // Attempt a key agreement with the private key from the first key pair and the public
+ // key from the second key pair.
+ KeyAgreement secondKa = KeyAgreement.getInstance("XDH");
+ secondKa.init(firstKeyPair.getPrivate());
+ secondKa.doPhase(secondKeyPair.getPublic(), true);
+ byte[] secondSecret = secondKa.generateSecret();
+
+ // Attempt a key agreement "the other way around": using the private key from the second
+ // key pair and the public key from the first key pair.
+ KeyAgreement firstKa = KeyAgreement.getInstance("XDH");
+ firstKa.init(secondKeyPair.getPrivate());
+ firstKa.doPhase(firstKeyPair.getPublic(), true);
+ byte[] firstSecret = firstKa.generateSecret();
+
+ // Both secrets being equal means the key agreement was successful.
+ assertThat(Arrays.compare(firstSecret, secondSecret)).isEqualTo(0);
}
@Test
