org.conscrypt.GCMParameters Maven / Gradle / Ivy
/*
* Copyright 2015 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.io.IOException;
import java.security.AlgorithmParametersSpi;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidParameterSpecException;
/**
* GCM parameters used during an ciphering operation with {@link OpenSSLCipher}.
* This class is used internally for backward compatibility with Android versions
* that did not have the {@code GCMParameterSpec} class, in addition to being the
* implementation of the GCM AlgorithmParameters implementation.
*
* The only supported encoding format is ASN.1, as specified in RFC 5084 section 3.2.
*
* @hide
*/
@Internal
public final class GCMParameters extends AlgorithmParametersSpi {
// The default value (in bits) for TLEN in the GCM ASN.1 module
private static final int DEFAULT_TLEN = 96;
/** The tag length in bits. */
private int tLen;
/** Actually the nonce value for the GCM operation. */
private byte[] iv;
public GCMParameters() { }
GCMParameters(int tLen, byte[] iv) {
this.tLen = tLen;
this.iv = iv;
}
/**
* Returns the tag length in bits.
*/
int getTLen() {
return tLen;
}
/**
* Returns a non-cloned version of the IV.
*/
byte[] getIV() {
return iv;
}
@Override
protected void engineInit(AlgorithmParameterSpec algorithmParameterSpec)
throws InvalidParameterSpecException {
GCMParameters params = Platform.fromGCMParameterSpec(algorithmParameterSpec);
if (params == null) {
throw new InvalidParameterSpecException("Only GCMParameterSpec is supported");
}
this.tLen = params.tLen;
this.iv = params.iv;
}
@Override
protected void engineInit(byte[] bytes) throws IOException {
long readRef = 0;
long seqRef = 0;
try {
readRef = NativeCrypto.asn1_read_init(bytes);
seqRef = NativeCrypto.asn1_read_sequence(readRef);
byte[] newIv = NativeCrypto.asn1_read_octetstring(seqRef);
int newTlen = DEFAULT_TLEN;
if (!NativeCrypto.asn1_read_is_empty(seqRef)) {
newTlen = 8 * (int) NativeCrypto.asn1_read_uint64(seqRef);
}
if (!NativeCrypto.asn1_read_is_empty(seqRef)
|| !NativeCrypto.asn1_read_is_empty(readRef)) {
throw new IOException("Error reading ASN.1 encoding");
}
this.iv = newIv;
this.tLen = newTlen;
} finally {
NativeCrypto.asn1_read_free(seqRef);
NativeCrypto.asn1_read_free(readRef);
}
}
@Override
protected void engineInit(byte[] bytes, String format) throws IOException {
if ((format == null) || format.equals("ASN.1")) {
engineInit(bytes);
} else {
throw new IOException("Unsupported format: " + format);
}
}
@Override
protected T engineGetParameterSpec(Class aClass)
throws InvalidParameterSpecException {
if ((aClass != null) && aClass.getName().equals("javax.crypto.spec.GCMParameterSpec")) {
return aClass.cast(Platform.toGCMParameterSpec(tLen, iv));
} else {
throw new InvalidParameterSpecException("Unsupported class: " + aClass);
}
}
@Override
protected byte[] engineGetEncoded() throws IOException {
long cbbRef = 0;
long seqRef = 0;
try {
cbbRef = NativeCrypto.asn1_write_init();
seqRef = NativeCrypto.asn1_write_sequence(cbbRef);
NativeCrypto.asn1_write_octetstring(seqRef, this.iv);
if (this.tLen != DEFAULT_TLEN) {
NativeCrypto.asn1_write_uint64(seqRef, this.tLen / 8);
}
return NativeCrypto.asn1_write_finish(cbbRef);
} catch (IOException e) {
NativeCrypto.asn1_write_cleanup(cbbRef);
throw e;
} finally {
NativeCrypto.asn1_write_free(seqRef);
NativeCrypto.asn1_write_free(cbbRef);
}
}
@Override
protected byte[] engineGetEncoded(String format) throws IOException {
if ((format == null) || format.equals("ASN.1")) {
return engineGetEncoded();
}
throw new IOException("Unsupported format: " + format);
}
@Override
protected String engineToString() {
return "Conscrypt GCM AlgorithmParameters";
}
}