ECDHDecrypter.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.security.PrivateKey;
import java.security.interfaces.ECPrivateKey;
import java.security.interfaces.ECPublicKey;
import java.util.Collections;
import java.util.LinkedHashSet;
import java.util.Set;
import javax.crypto.SecretKey;
import com.nimbusds.jose.*;
import com.nimbusds.jose.crypto.impl.AAD;
import com.nimbusds.jose.crypto.impl.CriticalHeaderParamsDeferral;
import com.nimbusds.jose.crypto.impl.ECDH;
import com.nimbusds.jose.crypto.impl.ECDHCryptoProvider;
import com.nimbusds.jose.crypto.utils.ECChecks;
import com.nimbusds.jose.jwk.Curve;
import com.nimbusds.jose.jwk.ECKey;
import com.nimbusds.jose.util.Base64URL;
/**
* Elliptic Curve Diffie-Hellman decrypter of
* {@link com.nimbusds.jose.JWEObject JWE objects} for curves using EC JWK
* keys. Expects a private EC key (with a P-256, P-384 or P-521 curve).
*
* <p>See RFC 7518
* <a href="https://tools.ietf.org/html/rfc7518#section-4.6">section 4.6</a>
* for more information.
*
* <p>For Curve25519/X25519, see {@link X25519Decrypter} instead.
*
* <p>This class is thread-safe.
*
* <p>Supports the following key management algorithms:
*
* <ul>
* <li>{@link com.nimbusds.jose.JWEAlgorithm#ECDH_ES}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#ECDH_ES_A128KW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#ECDH_ES_A192KW}
* <li>{@link com.nimbusds.jose.JWEAlgorithm#ECDH_ES_A256KW}
* </ul>
*
* <p>Supports the following elliptic curves:
*
* <ul>
* <li>{@link com.nimbusds.jose.jwk.Curve#P_256}
* <li>{@link com.nimbusds.jose.jwk.Curve#P_384}
* <li>{@link com.nimbusds.jose.jwk.Curve#P_521}
* </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 Vladimir Dzhuvinov
* @author Egor Puzanov
* @version 2023-05-17
*/
public class ECDHDecrypter extends ECDHCryptoProvider implements JWEDecrypter, CriticalHeaderParamsAware {
/**
* The supported EC JWK curves by the ECDH crypto provider class.
*/
public static final Set<Curve> SUPPORTED_ELLIPTIC_CURVES;
static {
Set<Curve> curves = new LinkedHashSet<>();
curves.add(Curve.P_256);
curves.add(Curve.P_384);
curves.add(Curve.P_521);
SUPPORTED_ELLIPTIC_CURVES = Collections.unmodifiableSet(curves);
}
/**
* The private EC key.
*/
private final PrivateKey privateKey;
/**
* The critical header policy.
*/
private final CriticalHeaderParamsDeferral critPolicy = new CriticalHeaderParamsDeferral();
/**
* Creates a new Elliptic Curve Diffie-Hellman decrypter.
*
* @param privateKey The private EC key. Must not be {@code null}.
*
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHDecrypter(final ECPrivateKey privateKey)
throws JOSEException {
this(privateKey, null);
}
/**
* Creates a new Elliptic Curve Diffie-Hellman decrypter.
*
* @param ecJWK The EC JSON Web Key (JWK). Must contain a private
* part. Must not be {@code null}.
*
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHDecrypter(final ECKey ecJWK)
throws JOSEException {
super(ecJWK.getCurve(), null);
if (! ecJWK.isPrivate()) {
throw new JOSEException("The EC JWK doesn't contain a private part");
}
this.privateKey = ecJWK.toECPrivateKey();
}
/**
* Creates a new Elliptic Curve Diffie-Hellman decrypter.
*
* @param privateKey The private EC key. 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 JOSEException If the elliptic curve is not supported.
*/
public ECDHDecrypter(final ECPrivateKey privateKey, final Set<String> defCritHeaders)
throws JOSEException {
this(privateKey, defCritHeaders, Curve.forECParameterSpec(privateKey.getParams()));
}
/**
* Creates a new Elliptic Curve Diffie-Hellman decrypter. This
* constructor can also accept a private EC key located in a PKCS#11
* store that doesn't expose the private key parameters (such as a
* smart card or HSM).
*
* @param privateKey The private EC key. 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 curve The key curve. Must not be {@code null}.
*
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHDecrypter(final PrivateKey privateKey,
final Set<String> defCritHeaders,
final Curve curve)
throws JOSEException {
super(curve, null);
critPolicy.setDeferredCriticalHeaderParams(defCritHeaders);
this.privateKey = privateKey;
}
/**
* Returns the private EC key.
*
* @return The private EC key. Casting to
* {@link java.security.interfaces.ECPrivateKey} may not be
* possible if the key is located in a PKCS#11 store that
* doesn't expose the private key parameters.
*/
public PrivateKey getPrivateKey() {
return privateKey;
}
@Override
public Set<Curve> supportedEllipticCurves() {
return SUPPORTED_ELLIPTIC_CURVES;
}
@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 {
critPolicy.ensureHeaderPasses(header);
// Get ephemeral EC key
ECKey ephemeralKey = (ECKey) header.getEphemeralPublicKey();
if (ephemeralKey == null) {
throw new JOSEException("Missing ephemeral public EC key \"epk\" JWE header parameter");
}
ECPublicKey ephemeralPublicKey = ephemeralKey.toECPublicKey();
// Curve check
if (getPrivateKey() instanceof ECPrivateKey) {
ECPrivateKey ecPrivateKey = (ECPrivateKey)getPrivateKey();
if (!ECChecks.isPointOnCurve(ephemeralPublicKey, ecPrivateKey)) {
throw new JOSEException("Invalid ephemeral public EC key: Point(s) not on the expected curve");
}
} else {
if (!ECChecks.isPointOnCurve(ephemeralPublicKey, getCurve().toECParameterSpec())) {
throw new JOSEException("Invalid ephemeral public EC key: Point(s) not on the expected curve");
}
}
// Derive 'Z'
SecretKey Z = ECDH.deriveSharedSecret(
ephemeralPublicKey,
privateKey,
getJCAContext().getKeyEncryptionProvider());
return decryptWithZ(header, aad, Z, encryptedKey, iv, cipherText, authTag);
}
}