Merge "Merge remote-tracking branch 'aosp/upstream-master' into merge-152-from-upstream"

1 files changed, 69 insertions, 0 deletions

diff --git a/bcprov/src/main/java/org/bouncycastle/crypto/tls/SimulatedTlsSRPIdentityManager.java b/bcprov/src/main/java/org/bouncycastle/crypto/tls/SimulatedTlsSRPIdentityManager.java
new file mode 100644
index 0000000..c48b4ad
--- /dev/null
+++ b/bcprov/src/main/java/org/bouncycastle/crypto/tls/SimulatedTlsSRPIdentityManager.java
@@ -0,0 +1,69 @@
+package org.bouncycastle.crypto.tls;
+
+import java.math.BigInteger;
+
+import org.bouncycastle.crypto.Mac;
+import org.bouncycastle.crypto.agreement.srp.SRP6VerifierGenerator;
+import org.bouncycastle.crypto.macs.HMac;
+import org.bouncycastle.crypto.params.KeyParameter;
+import org.bouncycastle.crypto.params.SRP6GroupParameters;
+import org.bouncycastle.util.Strings;
+
+/**
+ * An implementation of {@link TlsSRPIdentityManager} that simulates the existence of "unknown" identities
+ * to obscure the fact that there is no verifier for them. 
+ */
+public class SimulatedTlsSRPIdentityManager
+    implements TlsSRPIdentityManager
+{
+    private static final byte[] PREFIX_PASSWORD = Strings.toByteArray("password");
+    private static final byte[] PREFIX_SALT = Strings.toByteArray("salt");
+
+    /**
+     * Create a {@link SimulatedTlsSRPIdentityManager} that implements the algorithm from RFC 5054 2.5.1.3
+     *
+     * @param group the {@link SRP6GroupParameters} defining the group that SRP is operating in
+     * @param seedKey the secret "seed key" referred to in RFC 5054 2.5.1.3
+     * @return an instance of {@link SimulatedTlsSRPIdentityManager}
+     */
+    public static SimulatedTlsSRPIdentityManager getRFC5054Default(SRP6GroupParameters group, byte[] seedKey)
+    {
+        SRP6VerifierGenerator verifierGenerator = new SRP6VerifierGenerator();
+        verifierGenerator.init(group, TlsUtils.createHash(HashAlgorithm.sha1));
+
+        HMac mac = new HMac(TlsUtils.createHash(HashAlgorithm.sha1));
+        mac.init(new KeyParameter(seedKey));
+
+        return new SimulatedTlsSRPIdentityManager(group, verifierGenerator, mac);
+    }
+
+    protected SRP6GroupParameters group;
+    protected SRP6VerifierGenerator verifierGenerator;
+    protected Mac mac;
+
+    public SimulatedTlsSRPIdentityManager(SRP6GroupParameters group, SRP6VerifierGenerator verifierGenerator, Mac mac)
+    {
+        this.group = group;
+        this.verifierGenerator = verifierGenerator;
+        this.mac = mac;
+    }
+
+    public TlsSRPLoginParameters getLoginParameters(byte[] identity)
+    {
+        mac.update(PREFIX_SALT, 0, PREFIX_SALT.length);
+        mac.update(identity, 0, identity.length);
+
+        byte[] salt = new byte[mac.getMacSize()];
+        mac.doFinal(salt, 0);
+
+        mac.update(PREFIX_PASSWORD, 0, PREFIX_PASSWORD.length);
+        mac.update(identity, 0, identity.length);
+
+        byte[] password = new byte[mac.getMacSize()];
+        mac.doFinal(password, 0);
+
+        BigInteger verifier = verifierGenerator.generateVerifier(salt, identity, password);
+
+        return new TlsSRPLoginParameters(group, verifier, salt);
+    }
+}