From c822623677ab452428b5f69080c1736a52cfa311 Mon Sep 17 00:00:00 2001
From: str4d <str4d@mail.i2p>
Date: Tue, 2 Feb 2016 02:31:30 +0000
Subject: [PATCH] Migrate Bluetooth protocol to BQP's master secret derivation
---
.../api/crypto/CryptoComponent.java | 24 ++++++++++------
.../crypto/CryptoComponentImpl.java | 28 ++++---------------
.../briarproject/invitation/Connector.java | 2 +-
.../briarproject/crypto/KeyAgreementTest.java | 4 +--
4 files changed, 25 insertions(+), 33 deletions(-)
diff --git a/briar-api/src/org/briarproject/api/crypto/CryptoComponent.java b/briar-api/src/org/briarproject/api/crypto/CryptoComponent.java
index ac0842472c..0ba779202b 100644
--- a/briar-api/src/org/briarproject/api/crypto/CryptoComponent.java
+++ b/briar-api/src/org/briarproject/api/crypto/CryptoComponent.java
@@ -29,14 +29,6 @@ public interface CryptoComponent {
/** Generates a random invitation code. */
int generateBTInvitationCode();
- /**
- * Derives a shared master secret from two public keys and one of the
- * corresponding private keys.
- * @param alice whether the private key belongs to Alice or Bob.
- */
- SecretKey deriveBTMasterSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
- boolean alice) throws GeneralSecurityException;
-
/**
* Derives a confirmation code from the given master secret.
* @param alice whether the code is for use by Alice or Bob.
@@ -111,6 +103,22 @@ public interface CryptoComponent {
*/
SecretKey deriveMasterSecret(SecretKey sharedSecret);
+ /**
+ * Derives a master secret from two public keys and one of the corresponding
+ * private keys.
+ * <p/>
+ * Part of BQP. This is a helper method that calls
+ * deriveMasterSecret(deriveSharedSecret(theirPublicKey, ourKeyPair, alice))
+ *
+ * @param theirPublicKey the ephemeral public key of the remote party
+ * @param ourKeyPair our ephemeral keypair
+ * @param alice true if ourKeyPair belongs to Alice
+ * @return the shared secret
+ * @throws GeneralSecurityException
+ */
+ SecretKey deriveMasterSecret(byte[] theirPublicKey, KeyPair ourKeyPair,
+ boolean alice) throws GeneralSecurityException;
+
/**
* Derives initial transport keys for the given transport in the given
* rotation period from the given master secret.
diff --git a/briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java b/briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java
index 07916ab5ba..2a779f3fe2 100644
--- a/briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java
+++ b/briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java
@@ -205,28 +205,6 @@ class CryptoComponentImpl implements CryptoComponent {
return ByteUtils.readUint(random, CODE_BITS);
}
- public SecretKey deriveBTMasterSecret(byte[] theirPublicKey,
- KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
- MessageDigest messageDigest = getMessageDigest();
- byte[] ourPublicKey = ourKeyPair.getPublic().getEncoded();
- byte[] ourHash = messageDigest.digest(ourPublicKey);
- byte[] theirHash = messageDigest.digest(theirPublicKey);
- byte[] aliceInfo, bobInfo;
- if (alice) {
- aliceInfo = ourHash;
- bobInfo = theirHash;
- } else {
- aliceInfo = theirHash;
- bobInfo = ourHash;
- }
- PrivateKey ourPriv = ourKeyPair.getPrivate();
- PublicKey theirPub = agreementKeyParser.parsePublicKey(theirPublicKey);
- // The raw secret comes from the key agreement algorithm
- byte[] raw = performRawKeyAgreement(ourPriv, theirPub);
- // Derive the master secret from the raw secret using the hash KDF
- return new SecretKey(hashKdf(raw, BT_MASTER, aliceInfo, bobInfo));
- }
-
public int deriveBTConfirmationCode(SecretKey master, boolean alice) {
byte[] b = macKdf(master, alice ? BT_A_CONFIRM : BT_B_CONFIRM);
return ByteUtils.readUint(b, CODE_BITS);
@@ -290,6 +268,12 @@ class CryptoComponentImpl implements CryptoComponent {
return new SecretKey(macKdf(sharedSecret, MASTER_KEY));
}
+ public SecretKey deriveMasterSecret(byte[] theirPublicKey,
+ KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
+ return deriveMasterSecret(deriveSharedSecret(
+ theirPublicKey,ourKeyPair, alice));
+ }
+
public TransportKeys deriveTransportKeys(TransportId t,
SecretKey master, long rotationPeriod, boolean alice) {
// Keys for the previous period are derived from the master secret
diff --git a/briar-core/src/org/briarproject/invitation/Connector.java b/briar-core/src/org/briarproject/invitation/Connector.java
index 1a5ca82fba..a89aef88a5 100644
--- a/briar-core/src/org/briarproject/invitation/Connector.java
+++ b/briar-core/src/org/briarproject/invitation/Connector.java
@@ -146,7 +146,7 @@ abstract class Connector extends Thread {
// Derive the master secret
if (LOG.isLoggable(INFO))
LOG.info(pluginName + " deriving master secret");
- return crypto.deriveBTMasterSecret(key, keyPair, alice);
+ return crypto.deriveMasterSecret(key, keyPair, alice);
}
protected void sendConfirmation(BdfWriter w, boolean confirmed)
diff --git a/briar-tests/src/org/briarproject/crypto/KeyAgreementTest.java b/briar-tests/src/org/briarproject/crypto/KeyAgreementTest.java
index ff04f23d68..17d9768db9 100644
--- a/briar-tests/src/org/briarproject/crypto/KeyAgreementTest.java
+++ b/briar-tests/src/org/briarproject/crypto/KeyAgreementTest.java
@@ -20,8 +20,8 @@ public class KeyAgreementTest extends BriarTestCase {
byte[] aPub = aPair.getPublic().getEncoded();
KeyPair bPair = crypto.generateAgreementKeyPair();
byte[] bPub = bPair.getPublic().getEncoded();
- SecretKey aMaster = crypto.deriveBTMasterSecret(aPub, bPair, true);
- SecretKey bMaster = crypto.deriveBTMasterSecret(bPub, aPair, false);
+ SecretKey aMaster = crypto.deriveMasterSecret(aPub, bPair, true);
+ SecretKey bMaster = crypto.deriveMasterSecret(bPub, aPair, false);
assertArrayEquals(aMaster.getBytes(), bMaster.getBytes());
}
--
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