org.conscrypt.OpenSSLAeadCipherChaCha20 Maven / Gradle / Ivy
/*
* Copyright (C) 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.conscrypt;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
@Internal
public class OpenSSLAeadCipherChaCha20 extends OpenSSLAeadCipher {
public OpenSSLAeadCipherChaCha20() {
super(Mode.POLY1305);
}
@Override
void checkSupportedKeySize(int keyLength) throws InvalidKeyException {
if (keyLength != 32) {
throw new InvalidKeyException("Unsupported key size: " + keyLength
+ " bytes (must be 32)");
}
}
@Override
String getBaseCipherName() {
return "ChaCha20";
}
@Override
int getCipherBlockSize() {
return 0;
}
@Override
void checkSupportedMode(Mode mode) throws NoSuchAlgorithmException {
if (mode != Mode.POLY1305) {
throw new NoSuchAlgorithmException("Mode must be Poly1305");
}
}
@Override
long getEVP_AEAD(int keyLength) throws InvalidKeyException {
if (keyLength == 32) {
return NativeCrypto.EVP_aead_chacha20_poly1305();
} else {
throw new RuntimeException("Unexpected key length: " + keyLength);
}
}
@Override
int getOutputSizeForFinal(int inputLen) {
// For ChaCha20+Poly1305, the tag is always 16 bytes long and there is no
// padding or other concerns, so we can calculate the exact length required
// without a native call
if (isEncrypting()) {
return bufCount + inputLen + 16;
} else {
return Math.max(0, bufCount + inputLen - 16);
}
}
}