org.jose4j.jwe.Pbes2HmacShaWithAesKeyWrapAlgorithm Maven / Gradle / Ivy
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The jose.4.j library is a robust and easy to use open source implementation of JSON Web Token (JWT) and the JOSE specification suite (JWS, JWE, and JWK).
It is written in Java and relies solely on the JCA APIs for cryptography.
Please see https://bitbucket.org/b_c/jose4j/wiki/Home for more info, examples, etc..
/*
* Copyright 2012-2017 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;
import org.jose4j.base64url.Base64Url;
import org.jose4j.jca.ProviderContext;
import org.jose4j.jwa.AlgorithmInfo;
import org.jose4j.jwa.CryptoPrimitive;
import org.jose4j.jwe.kdf.PasswordBasedKeyDerivationFunction2;
import org.jose4j.jwx.HeaderParameterNames;
import org.jose4j.jwx.Headers;
import org.jose4j.jwx.KeyValidationSupport;
import org.jose4j.keys.AesKey;
import org.jose4j.keys.KeyPersuasion;
import org.jose4j.keys.PbkdfKey;
import org.jose4j.lang.ByteUtil;
import org.jose4j.lang.InvalidKeyException;
import org.jose4j.lang.JoseException;
import org.jose4j.lang.StringUtil;
import org.jose4j.mac.MacUtil;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
/**
*/
public class Pbes2HmacShaWithAesKeyWrapAlgorithm extends AlgorithmInfo implements KeyManagementAlgorithm
{
private static final byte[] ZERO_BYTE = new byte[]{0};
private AesKeyWrapManagementAlgorithm keyWrap;
private ContentEncryptionKeyDescriptor keyWrapKeyDescriptor;
private PasswordBasedKeyDerivationFunction2 pbkdf2;
// RFC 2898 and JWA both recommend a minimum iteration count of 1000 and mandate at least 8 bytes of salt
// so we'll go with defaults that somewhat exceed those requirements/recommendations
private long defaultIterationCount = 8192L * 8;
private int defaultSaltByteLength = 12;
public Pbes2HmacShaWithAesKeyWrapAlgorithm(String alg, String hmacAlg, AesKeyWrapManagementAlgorithm keyWrapAlg)
{
setAlgorithmIdentifier(alg);
setJavaAlgorithm("n/a");
pbkdf2 = new PasswordBasedKeyDerivationFunction2(hmacAlg);
setKeyPersuasion(KeyPersuasion.SYMMETRIC);
setKeyType(PbkdfKey.ALGORITHM);
keyWrap = keyWrapAlg;
keyWrapKeyDescriptor = new ContentEncryptionKeyDescriptor(keyWrap.getKeyByteLength(), AesKey.ALGORITHM);
}
@Override
public ContentEncryptionKeys manageForEncrypt(Key managementKey, ContentEncryptionKeyDescriptor cekDesc, Headers headers, byte[] cekOverride, ProviderContext providerContext) throws JoseException
{
Key derivedKey = deriveForEncrypt(managementKey, headers, providerContext);
return keyWrap.manageForEncrypt(derivedKey, cekDesc, headers, cekOverride, providerContext);
}
protected Key deriveForEncrypt(Key managementKey, Headers headers, ProviderContext providerContext) throws JoseException
{
Long iterationCount = headers.getLongHeaderValue(HeaderParameterNames.PBES2_ITERATION_COUNT);
if (iterationCount == null)
{
iterationCount = defaultIterationCount;
headers.setObjectHeaderValue(HeaderParameterNames.PBES2_ITERATION_COUNT, iterationCount);
}
if (iterationCount < 1000)
{
throw new JoseException("iteration count ("+HeaderParameterNames.PBES2_ITERATION_COUNT+"="+
iterationCount+") cannot be less than 1000 (and should probably be considerably more)");
}
String saltInputString = headers.getStringHeaderValue(HeaderParameterNames.PBES2_SALT_INPUT);
byte[] saltInput;
Base64Url base64Url = new Base64Url();
if (saltInputString == null)
{
saltInput = ByteUtil.randomBytes(defaultSaltByteLength, providerContext.getSecureRandom());
saltInputString = base64Url.base64UrlEncode(saltInput);
headers.setStringHeaderValue(HeaderParameterNames.PBES2_SALT_INPUT, saltInputString);
}
else
{
saltInput = base64Url.base64UrlDecode(saltInputString);
}
if (saltInput.length < 8)
{
throw new JoseException("A p2s salt input value containing 8 or more octets MUST be used.");
}
return deriveKey(managementKey, iterationCount, saltInput, providerContext);
}
@Override
public CryptoPrimitive prepareForDecrypt(Key managementKey, Headers headers, ProviderContext providerContext) throws JoseException
{
Long iterationCount = headers.getLongHeaderValue(HeaderParameterNames.PBES2_ITERATION_COUNT);
String saltInputString = headers.getStringHeaderValue(HeaderParameterNames.PBES2_SALT_INPUT);
Base64Url base64Url = new Base64Url();
byte[] saltInput = base64Url.base64UrlDecode(saltInputString);
Key derivedKey = deriveKey(managementKey, iterationCount, saltInput, providerContext);
return new CryptoPrimitive(derivedKey);
}
@Override
public Key manageForDecrypt(CryptoPrimitive cryptoPrimitive, byte[] encryptedKey, ContentEncryptionKeyDescriptor cekDesc, Headers headers, ProviderContext providerContext) throws JoseException
{
Key derivedKey = cryptoPrimitive.getKey();
CryptoPrimitive wrapCryptoPrimitive = keyWrap.prepareForDecrypt(derivedKey, headers, providerContext);
return keyWrap.manageForDecrypt(wrapCryptoPrimitive, encryptedKey, cekDesc, headers, providerContext);
}
private Key deriveKey(Key managementKey, Long iterationCount, byte[] saltInput, ProviderContext providerContext) throws JoseException
{
byte[] salt = ByteUtil.concat(StringUtil.getBytesUtf8(getAlgorithmIdentifier()), ZERO_BYTE, saltInput);
int dkLen = keyWrapKeyDescriptor.getContentEncryptionKeyByteLength();
String macProvider = providerContext.getSuppliedKeyProviderContext().getMacProvider();
byte[] derivedKeyBytes = pbkdf2.derive(managementKey.getEncoded(), salt, iterationCount.intValue(), dkLen, macProvider);
return new SecretKeySpec(derivedKeyBytes, keyWrapKeyDescriptor.getContentEncryptionKeyAlgorithm());
}
@Override
public void validateEncryptionKey(Key managementKey, ContentEncryptionAlgorithm contentEncryptionAlg) throws InvalidKeyException
{
validateKey(managementKey);
}
@Override
public void validateDecryptionKey(Key managementKey, ContentEncryptionAlgorithm contentEncryptionAlg) throws InvalidKeyException
{
validateKey(managementKey);
}
public void validateKey(Key managementKey) throws InvalidKeyException
{
KeyValidationSupport.notNull(managementKey);
}
@Override
public boolean isAvailable()
{
return keyWrap.isAvailable();
}
public long getDefaultIterationCount()
{
return defaultIterationCount;
}
public void setDefaultIterationCount(long defaultIterationCount)
{
this.defaultIterationCount = defaultIterationCount;
}
public int getDefaultSaltByteLength()
{
return defaultSaltByteLength;
}
public void setDefaultSaltByteLength(int defaultSaltByteLength)
{
this.defaultSaltByteLength = defaultSaltByteLength;
}
public static class HmacSha256Aes128 extends Pbes2HmacShaWithAesKeyWrapAlgorithm
{
public HmacSha256Aes128()
{
super(KeyManagementAlgorithmIdentifiers.PBES2_HS256_A128KW, MacUtil.HMAC_SHA256, new AesKeyWrapManagementAlgorithm.Aes128().setUseGeneralProviderContext());
}
}
public static class HmacSha384Aes192 extends Pbes2HmacShaWithAesKeyWrapAlgorithm
{
public HmacSha384Aes192()
{
super(KeyManagementAlgorithmIdentifiers.PBES2_HS384_A192KW, MacUtil.HMAC_SHA384, new AesKeyWrapManagementAlgorithm.Aes192().setUseGeneralProviderContext());
}
}
public static class HmacSha512Aes256 extends Pbes2HmacShaWithAesKeyWrapAlgorithm
{
public HmacSha512Aes256()
{
super(KeyManagementAlgorithmIdentifiers.PBES2_HS512_A256KW, MacUtil.HMAC_SHA512, new AesKeyWrapManagementAlgorithm.Aes256().setUseGeneralProviderContext());
}
}
}