AESDecrypter.java
/*
* nimbus-jose-jwt
*
* Copyright 2012-2016, Connect2id Ltd.
*
* 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 com.nimbusds.jose.crypto;
import java.util.Set;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import com.nimbusds.jose.crypto.impl.*;
import net.jcip.annotations.ThreadSafe;
import com.nimbusds.jose.*;
import com.nimbusds.jose.jwk.OctetSequenceKey;
import com.nimbusds.jose.util.Base64URL;
/**
* AES and AES GCM key wrap decrypter of {@link com.nimbusds.jose.JWEObject JWE
* objects}. Expects an AES key.
*
* <p>Unwraps the encrypted Content Encryption Key (CEK) with the specified AES
* key, and then uses the CEK along with the IV and authentication tag to
* decrypt the cipher text. See RFC 7518, sections
* <a href="https://tools.ietf.org/html/rfc7518#section-4.4">4.4</a> and
* <a href="https://tools.ietf.org/html/rfc7518#section-4.7">4.7</a> for more
* information.
*
* <p>This class is thread-safe.
*
* <p>Supports the following key management algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A128KW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A192KW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A256KW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A128GCMKW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A192GCMKW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#A256GCMKW}
* </ul>
*
* <p>Supports the following content encryption algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192CBC_HS384}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256GCM}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256_DEPRECATED}
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512_DEPRECATED}
* <li>{@link com.nimbusds.jose.EncryptionMethod#XC20P}
* </ul>
*
* @author Melisa Halsband
* @author Vladimir Dzhuvinov
* @author Egor Puzanov
* @version 2023-09-10
*/
@ThreadSafe
public class AESDecrypter extends AESCryptoProvider implements JWEDecrypter, CriticalHeaderParamsAware {
/**
* The critical header policy.
*/
private final CriticalHeaderParamsDeferral critPolicy = new CriticalHeaderParamsDeferral();
/**
* Creates a new AES decrypter.
*
* @param kek The Key Encrypting Key. Must be 128 bits (16 bytes), 192
* bits (24 bytes) or 256 bits (32 bytes). Must not be
* {@code null}.
*
* @throws KeyLengthException If the KEK length is invalid.
*/
public AESDecrypter(final SecretKey kek)
throws KeyLengthException {
this(kek, null);
}
/**
* Creates a new AES decrypter.
*
* @param keyBytes The Key Encrypting Key, as a byte array. Must be 128
* bits (16 bytes), 192 bits (24 bytes) or 256 bits (32
* bytes). Must not be {@code null}.
*
* @throws KeyLengthException If the KEK length is invalid.
*/
public AESDecrypter(final byte[] keyBytes)
throws KeyLengthException {
this(new SecretKeySpec(keyBytes, "AES"));
}
/**
* Creates a new AES decrypter.
*
* @param octJWK The Key Encryption Key, as a JWK. Must be 128 bits (16
* bytes), 192 bits (24 bytes), 256 bits (32 bytes), 384
* bits (48 bytes) or 512 bits (64 bytes) long. Must not
* be {@code null}.
*
* @throws KeyLengthException If the KEK length is invalid.
*/
public AESDecrypter(final OctetSequenceKey octJWK)
throws KeyLengthException {
this(octJWK.toSecretKey("AES"));
}
/**
* Creates a new AES decrypter.
*
* @param kek The Key Encrypting Key. Must be 128 bits (16
* bytes), 192 bits (24 bytes) or 256 bits (32
* bytes). Must not be {@code null}.
* @param defCritHeaders The names of the critical header parameters
* that are deferred to the application for
* processing, empty set or {@code null} if none.
*
* @throws KeyLengthException If the KEK length is invalid.
*/
public AESDecrypter(final SecretKey kek, final Set<String> defCritHeaders)
throws KeyLengthException {
super(kek, null);
critPolicy.setDeferredCriticalHeaderParams(defCritHeaders);
}
@Override
public Set<String> getProcessedCriticalHeaderParams() {
return critPolicy.getProcessedCriticalHeaderParams();
}
@Override
public Set<String> getDeferredCriticalHeaderParams() {
return critPolicy.getProcessedCriticalHeaderParams();
}
/**
* Decrypts the specified cipher text of a {@link JWEObject JWE Object}.
*
* @param header The JSON Web Encryption (JWE) header. Must
* specify a supported JWE algorithm and method.
* Must not be {@code null}.
* @param encryptedKey The encrypted key, {@code null} if not required
* by the JWE algorithm.
* @param iv The initialisation vector, {@code null} if not
* required by the JWE algorithm.
* @param cipherText The cipher text to decrypt. Must not be
* {@code null}.
* @param authTag The authentication tag, {@code null} if not
* required.
*
* @return The clear text.
*
* @throws JOSEException If the JWE algorithm or method is not
* supported, if a critical header parameter is
* not supported or marked for deferral to the
* application, or if decryption failed for some
* other reason.
*/
@Deprecated
public byte[] decrypt(final JWEHeader header,
final Base64URL encryptedKey,
final Base64URL iv,
final Base64URL cipherText,
final Base64URL authTag)
throws JOSEException {
return decrypt(header, encryptedKey, iv, cipherText, authTag, AAD.compute(header));
}
@Override
public byte[] decrypt(final JWEHeader header,
final Base64URL encryptedKey,
final Base64URL iv,
final Base64URL cipherText,
final Base64URL authTag,
final byte[] aad)
throws JOSEException {
// Validate required JWE parts
if (encryptedKey == null) {
throw new JOSEException("Missing JWE encrypted key");
}
if (iv == null) {
throw new JOSEException("Missing JWE initialization vector (IV)");
}
if (authTag == null) {
throw new JOSEException("Missing JWE authentication tag");
}
// Derive the content encryption key
JWEAlgorithm alg = JWEHeaderValidation.getAlgorithmAndEnsureNotNull(header);
critPolicy.ensureHeaderPasses(header);
int keyLength = header.getEncryptionMethod().cekBitLength();
final SecretKey cek;
if (alg.equals(JWEAlgorithm.A128KW) ||
alg.equals(JWEAlgorithm.A192KW) ||
alg.equals(JWEAlgorithm.A256KW)) {
cek = AESKW.unwrapCEK(getKey(), encryptedKey.decode(), getJCAContext().getKeyEncryptionProvider());
} else if (alg.equals(JWEAlgorithm.A128GCMKW) ||
alg.equals(JWEAlgorithm.A192GCMKW) ||
alg.equals(JWEAlgorithm.A256GCMKW)) {
if (header.getIV() == null) {
throw new JOSEException("Missing JWE \"iv\" header parameter");
}
byte[] keyIV = header.getIV().decode();
if (header.getAuthTag() == null) {
throw new JOSEException("Missing JWE \"tag\" header parameter");
}
byte[] keyTag = header.getAuthTag().decode();
AuthenticatedCipherText authEncrCEK = new AuthenticatedCipherText(encryptedKey.decode(), keyTag);
cek = AESGCMKW.decryptCEK(getKey(), keyIV, authEncrCEK, keyLength, getJCAContext().getKeyEncryptionProvider());
} else {
throw new JOSEException(AlgorithmSupportMessage.unsupportedJWEAlgorithm(alg, SUPPORTED_ALGORITHMS));
}
return ContentCryptoProvider.decrypt(header, aad, encryptedKey, iv, cipherText, authTag, cek, getJCAContext());
}
}