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Implement BQP crypto

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This commit is contained in:
str4d
2016-01-28 06:53:20 +00:00
parent 4d7a23779a
commit 77e4ec381a
4 changed files with 134 additions and 0 deletions
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59
briar-core/src/org/briarproject/crypto/CryptoComponentImpl.java
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@@ -40,6 +40,7 @@ import javax.inject.Inject;
import static java.util.logging.Level.INFO;
import static org.briarproject.api.invitation.InvitationConstants.CODE_BITS;
import static org.briarproject.api.keyagreement.KeyAgreementConstants.COMMIT_LENGTH;
import static org.briarproject.api.transport.TransportConstants.TAG_LENGTH;
import static org.briarproject.crypto.EllipticCurveConstants.PARAMETERS;
import static org.briarproject.util.ByteUtils.INT_32_BYTES;
@@ -73,6 +74,14 @@ class CryptoComponentImpl implements CryptoComponent {
// KDF labels for bluetooth signature nonce derivation
private static final byte[] BT_A_NONCE = ascii("ALICE_SIGNATURE_NONCE");
private static final byte[] BT_B_NONCE = ascii("BOB_SIGNATURE_NONCE");
// Hash label for BQP public key commitment derivation
private static final byte[] COMMIT = ascii("COMMIT");
// Hash label for BQP shared secret derivation
private static final byte[] SHARED_SECRET = ascii("SHARED_SECRET");
// KDF label for BQP confirmation key derivation
private static final byte[] CONFIRMATION_KEY = ascii("CONFIRMATION_KEY");
// KDF label for BQP master key derivation
private static final byte[] MASTER_KEY = ascii("MASTER_KEY");
// KDF labels for tag key derivation
private static final byte[] A_TAG = ascii("ALICE_TAG_KEY");
private static final byte[] B_TAG = ascii("BOB_TAG_KEY");
@@ -231,6 +240,56 @@ class CryptoComponentImpl implements CryptoComponent {
return macKdf(master, alice ? BT_A_NONCE : BT_B_NONCE);
}
public byte[] deriveKeyCommitment(byte[] publicKey) {
byte[] hash = hash(COMMIT, publicKey);
// The output is the first COMMIT_LENGTH bytes of the hash
byte[] commitment = new byte[COMMIT_LENGTH];
System.arraycopy(hash, 0, commitment, 0, COMMIT_LENGTH);
return commitment;
}
public SecretKey deriveSharedSecret(byte[] theirPublicKey,
KeyPair ourKeyPair, boolean alice) throws GeneralSecurityException {
PrivateKey ourPriv = ourKeyPair.getPrivate();
PublicKey theirPub = agreementKeyParser.parsePublicKey(theirPublicKey);
byte[] raw = performRawKeyAgreement(ourPriv, theirPub);
byte[] alicePub, bobPub;
if (alice) {
alicePub = ourKeyPair.getPublic().getEncoded();
bobPub = theirPublicKey;
} else {
alicePub = theirPublicKey;
bobPub = ourKeyPair.getPublic().getEncoded();
}
return new SecretKey(hash(SHARED_SECRET, raw, alicePub, bobPub));
}
public byte[] deriveConfirmationRecord(SecretKey sharedSecret,
byte[] theirPayload, byte[] ourPayload, byte[] theirPublicKey,
KeyPair ourKeyPair, boolean alice, boolean aliceRecord) {
SecretKey ck = new SecretKey(macKdf(sharedSecret, CONFIRMATION_KEY));
byte[] alicePayload, alicePub, bobPayload, bobPub;
if (alice) {
alicePayload = ourPayload;
alicePub = ourKeyPair.getPublic().getEncoded();
bobPayload = theirPayload;
bobPub = theirPublicKey;
} else {
alicePayload = theirPayload;
alicePub = theirPublicKey;
bobPayload = ourPayload;
bobPub = ourKeyPair.getPublic().getEncoded();
}
if (aliceRecord)
return macKdf(ck, alicePayload, alicePub, bobPayload, bobPub);
else
return macKdf(ck, bobPayload, bobPub, alicePayload, alicePub);
}
public SecretKey deriveMasterSecret(SecretKey sharedSecret) {
return new SecretKey(macKdf(sharedSecret, MASTER_KEY));
}
public TransportKeys deriveTransportKeys(TransportId t,
SecretKey master, long rotationPeriod, boolean alice) {
// Keys for the previous period are derived from the master secret