DirectDecrypter.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.*;
import com.nimbusds.jose.crypto.impl.*;
import com.nimbusds.jose.jwk.OctetSequenceKey;
import com.nimbusds.jose.util.Base64URL;
import net.jcip.annotations.ThreadSafe;
/**
* Direct decrypter of {@link com.nimbusds.jose.JWEObject JWE objects} with a
* shared symmetric key.
*
* <p>See RFC 7518
* <a href="https://tools.ietf.org/html/rfc7518#section-4.5">section 4.5</a>
* for more information.</p>
*
* <p>This class is thread-safe.
*
* <p>Supports the following key management algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.JWEAlgorithm#DIR}
* </ul>
*
* <p>Supports the following content encryption algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256} (requires 256 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192CBC_HS384} (requires 384 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512} (requires 512 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128GCM} (requires 128 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A192GCM} (requires 192 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256GCM} (requires 256 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A128CBC_HS256_DEPRECATED} (requires 256 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#A256CBC_HS512_DEPRECATED} (requires 512 bit key)
* <li>{@link com.nimbusds.jose.EncryptionMethod#XC20P} (requires 256 bit key)
* </ul>
*
* <p>Also supports a promiscuous mode to decrypt any JWE by passing the
* content encryption key (CEK) directly. The that mode the JWE algorithm
* checks for ("alg":"dir") and encrypted key not being present will be
* skipped.
*
* @author Vladimir Dzhuvinov
* @author Egor Puzanov
* @version 2023-09-10
*/
@ThreadSafe
public class DirectDecrypter extends DirectCryptoProvider implements JWEDecrypter, CriticalHeaderParamsAware {
/**
* If set skips the checks for alg "dir" and encrypted key not present.
*/
private final boolean promiscuousMode;
/**
* The critical header policy.
*/
private final CriticalHeaderParamsDeferral critPolicy = new CriticalHeaderParamsDeferral();
/**
* Creates a new direct decrypter.
*
* @param key The symmetric key. Its algorithm should be "AES". 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 symmetric key length is not
* compatible.
*/
public DirectDecrypter(final SecretKey key)
throws KeyLengthException {
this(key, false);
}
/**
* Creates a new direct decrypter with the option to set it in
* promiscuous mode.
*
* @param key The symmetric key. Its algorithm should be
* "AES". 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}.
* @param promiscuousMode If {@code true} set the decrypter in
* promiscuous mode to permit decryption of any
* JWE with the supplied symmetric key. The that
* mode the JWE algorithm checks for
* ("alg":"dir") and encrypted key not being
* present will be skipped.
*
* @throws KeyLengthException If the symmetric key length is not
* compatible.
*/
public DirectDecrypter(final SecretKey key, final boolean promiscuousMode)
throws KeyLengthException {
super(key);
this.promiscuousMode = promiscuousMode;
}
/**
* Creates a new direct decrypter.
*
* @param keyBytes The symmetric key, as a byte array. 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 symmetric key length is not
* compatible.
*/
public DirectDecrypter(final byte[] keyBytes)
throws KeyLengthException {
this(new SecretKeySpec(keyBytes, "AES"), false);
}
/**
* Creates a new direct decrypter.
*
* @param octJWK The symmetric 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 symmetric key length is not
* compatible.
*/
public DirectDecrypter(final OctetSequenceKey octJWK)
throws KeyLengthException {
this(octJWK.toSecretKey("AES"));
}
/**
* Creates a new direct decrypter with the option to set it in
* promiscuous mode.
*
* @param key The symmetric key. Its algorithm should be
* "AES". 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}.
* @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 symmetric key length is not
* compatible.
*/
public DirectDecrypter(final SecretKey key, final Set<String> defCritHeaders)
throws KeyLengthException {
this(key, defCritHeaders, false);
}
/**
* Creates a new direct decrypter.
*
* @param key The symmetric key. Its algorithm should be
* "AES". 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}.
* @param defCritHeaders The names of the critical header parameters
* that are deferred to the application for
* processing, empty set or {@code null} if none.
*@param promiscuousMode If {@code true} set the decrypter in
* promiscuous mode to permit decryption of any
* JWE with the supplied symmetric key. The that
* mode the JWE algorithm checks for
* ("alg":"dir") and encrypted key not being
* present will be skipped.
*
* @throws KeyLengthException If the symmetric key length is not
* compatible.
*/
public DirectDecrypter(final SecretKey key,
final Set<String> defCritHeaders,
final boolean promiscuousMode)
throws KeyLengthException {
super(key);
critPolicy.setDeferredCriticalHeaderParams(defCritHeaders);
this.promiscuousMode = promiscuousMode;
}
@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 (! promiscuousMode) {
JWEAlgorithm alg = JWEHeaderValidation.getAlgorithmAndEnsureNotNull(header);
if (!alg.equals(JWEAlgorithm.DIR)) {
throw new JOSEException(AlgorithmSupportMessage.unsupportedJWEAlgorithm(alg, SUPPORTED_ALGORITHMS));
}
if (encryptedKey != null) {
throw new JOSEException("Unexpected present JWE encrypted key");
}
}
if (iv == null) {
throw new JOSEException("Unexpected present JWE initialization vector (IV)");
}
if (authTag == null) {
throw new JOSEException("Missing JWE authentication tag");
}
critPolicy.ensureHeaderPasses(header);
return ContentCryptoProvider.decrypt(header, aad, null, iv, cipherText, authTag, getKey(), getJCAContext());
}
}