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SealedSessionCipher encrypt

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This commit is contained in:
Jack Lloyd
2020-11-17 16:32:25 -05:00
parent ddda1a3635
commit 405d071ead
8 changed files with 239 additions and 38 deletions
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2
java/java/src/main/java/org/signal/internal/Native.java
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@@ -136,6 +136,8 @@ public final class Native {
public static native boolean ScannableFingerprint_Compare(byte[] fprint1, byte[] fprint2);
public static native byte[] SealedSessionCipher_Encrypt(long destination, long senderCert, byte[] ptext, SessionStore sessionStore, IdentityKeyStore identityStore);
public static native long SenderCertificate_Deserialize(byte[] data);
public static native void SenderCertificate_Destroy(long handle);
public static native byte[] SenderCertificate_GetCertificate(long handle);

45
java/java/src/main/java/org/signal/libsignal/metadata/SealedSessionCipher.java
View File

@@ -30,6 +30,8 @@ import org.whispersystems.libsignal.state.SignalProtocolStore;
import org.whispersystems.libsignal.util.ByteUtil;
import org.whispersystems.libsignal.util.guava.Optional;
import org.signal.client.internal.Native;
import java.security.InvalidAlgorithmParameterException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
@@ -67,21 +69,12 @@ public class SealedSessionCipher {
public byte[] encrypt(SignalProtocolAddress destinationAddress, SenderCertificate senderCertificate, byte[] paddedPlaintext)
throws InvalidKeyException, UntrustedIdentityException
{
CiphertextMessage message = new SessionCipher(signalProtocolStore, destinationAddress).encrypt(paddedPlaintext);
IdentityKeyPair ourIdentity = signalProtocolStore.getIdentityKeyPair();
ECPublicKey theirIdentity = signalProtocolStore.getIdentity(destinationAddress).getPublicKey();
ECKeyPair ephemeral = Curve.generateKeyPair();
byte[] ephemeralSalt = ByteUtil.combine("UnidentifiedDelivery".getBytes(), theirIdentity.serialize(), ephemeral.getPublicKey().serialize());
EphemeralKeys ephemeralKeys = calculateEphemeralKeys(theirIdentity, ephemeral.getPrivateKey(), ephemeralSalt);
byte[] staticKeyCiphertext = encrypt(ephemeralKeys.cipherKey, ephemeralKeys.macKey, ourIdentity.getPublicKey().getPublicKey().serialize());
byte[] staticSalt = ByteUtil.combine(ephemeralKeys.chainKey, staticKeyCiphertext);
StaticKeys staticKeys = calculateStaticKeys(theirIdentity, ourIdentity.getPrivateKey(), staticSalt);
UnidentifiedSenderMessageContent content = new UnidentifiedSenderMessageContent(message.getType(), senderCertificate, message.serialize());
byte[] messageBytes = encrypt(staticKeys.cipherKey, staticKeys.macKey, content.getSerialized());
return new UnidentifiedSenderMessage(ephemeral.getPublicKey(), staticKeyCiphertext, messageBytes).getSerialized();
return Native.SealedSessionCipher_Encrypt(
destinationAddress.nativeHandle(),
senderCertificate.nativeHandle(),
paddedPlaintext,
this.signalProtocolStore,
this.signalProtocolStore);
}
public DecryptionResult decrypt(CertificateValidator validator, byte[] ciphertext, long timestamp)
@@ -159,7 +152,7 @@ public class SealedSessionCipher {
private EphemeralKeys calculateEphemeralKeys(ECPublicKey ephemeralPublic, ECPrivateKey ephemeralPrivate, byte[] salt) throws InvalidKeyException {
try {
byte[] ephemeralSecret = Curve.calculateAgreement(ephemeralPublic, ephemeralPrivate);
byte[] ephemeralDerived = new HKDFv3().deriveSecrets(ephemeralSecret, salt, new byte[0], 96);
byte[] ephemeralDerived = new HKDFv3().deriveSecrets(ephemeralSecret, salt, null, 96);
byte[][] ephemeralDerivedParts = ByteUtil.split(ephemeralDerived, 32, 32, 32);
return new EphemeralKeys(ephemeralDerivedParts[0], ephemeralDerivedParts[1], ephemeralDerivedParts[2]);
@@ -171,7 +164,7 @@ public class SealedSessionCipher {
private StaticKeys calculateStaticKeys(ECPublicKey staticPublic, ECPrivateKey staticPrivate, byte[] salt) throws InvalidKeyException {
try {
byte[] staticSecret = Curve.calculateAgreement(staticPublic, staticPrivate);
byte[] staticDerived = new HKDFv3().deriveSecrets(staticSecret, salt, new byte[0], 96);
byte[] staticDerived = new HKDFv3().deriveSecrets(staticSecret, salt, null, 96);
byte[][] staticDerivedParts = ByteUtil.split(staticDerived, 32, 32, 32);
return new StaticKeys(staticDerivedParts[1], staticDerivedParts[2]);
@@ -192,24 +185,6 @@ public class SealedSessionCipher {
}
}
private byte[] encrypt(SecretKeySpec cipherKey, SecretKeySpec macKey, byte[] plaintext) {
try {
Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, cipherKey, new IvParameterSpec(new byte[16]));
Mac mac = Mac.getInstance("HmacSHA256");
mac.init(macKey);
byte[] ciphertext = cipher.doFinal(plaintext);
byte[] ourFullMac = mac.doFinal(ciphertext);
byte[] ourMac = ByteUtil.trim(ourFullMac, 10);
return ByteUtil.combine(ciphertext, ourMac);
} catch (NoSuchAlgorithmException | NoSuchPaddingException | java.security.InvalidKeyException | BadPaddingException | IllegalBlockSizeException | InvalidAlgorithmParameterException e) {
throw new AssertionError(e);
}
}
private byte[] decrypt(SecretKeySpec cipherKey, SecretKeySpec macKey, byte[] ciphertext) throws InvalidMacException {
try {
if (ciphertext.length < 10) {