org.jose4j.jwe.kdf.KdfUtil Maven / Gradle / Ivy
/*
* Copyright 2012-2021 Brian Campbell
*
* 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.jose4j.jwe.kdf;
import org.jose4j.base64url.Base64Url;
import org.jose4j.lang.ByteUtil;
import org.jose4j.lang.StringUtil;
/**
*/
public class KdfUtil
{
private Base64Url base64Url = new Base64Url();;
private ConcatenationKeyDerivationFunctionWithSha256 kdf;
public KdfUtil()
{
this(null);
}
public KdfUtil(String provider)
{
kdf = ConcatKeyDerivationFunctionFactory.make(provider);
}
public byte[] kdf(byte[] sharedSecret, int keydatalen, String algorithmId, String partyUInfo, String partyVInfo)
{
byte[] algorithmIdBytes = prependDatalen(StringUtil.getBytesUtf8(algorithmId));
byte[] partyUInfoBytes = getDatalenDataFormat(partyUInfo);
byte[] partyVInfoBytes = getDatalenDataFormat(partyVInfo);
byte[] suppPubInfo = ByteUtil.getBytes(keydatalen);
byte[] suppPrivInfo = ByteUtil.EMPTY_BYTES;
byte[] otherInfo = ByteUtil.concat(algorithmIdBytes, partyUInfoBytes, partyVInfoBytes, suppPubInfo, suppPrivInfo);
return kdf.kdf(sharedSecret, keydatalen, otherInfo);
}
byte[] prependDatalen(byte[] data)
{
if (data == null)
{
data = ByteUtil.EMPTY_BYTES;
}
byte[] datalen = ByteUtil.getBytes(data.length);
return ByteUtil.concat(datalen, data);
}
byte[] getDatalenDataFormat(String encodedValue)
{
byte[] data = base64Url.base64UrlDecode(encodedValue);
return prependDatalen(data);
}
}