ECDHEncrypter.java
/*
* nimbus-jose-jwt
*
* Copyright 2012-2019, 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.InvalidAlgorithmParameterException;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;
import java.security.interfaces.ECPrivateKey;
import java.security.interfaces.ECPublicKey;
import java.security.spec.ECParameterSpec;
import java.util.Arrays;
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.ECDH;
import com.nimbusds.jose.crypto.impl.ECDHCryptoProvider;
import com.nimbusds.jose.jwk.Curve;
import com.nimbusds.jose.jwk.ECKey;
import net.jcip.annotations.ThreadSafe;
/**
* Elliptic Curve Diffie-Hellman encrypter of
* {@link com.nimbusds.jose.JWEObject JWE objects} for curves using EC JWK keys.
* Expects a public 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 X25519Encrypter} 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 Tim McLean
* @author Vladimir Dzhuvinov
* @author Fernando Gonz��lez Callejas
* @author Egor Puzanov
* @version 2023-05-17
*/
@ThreadSafe
public class ECDHEncrypter extends ECDHCryptoProvider implements JWEEncrypter {
/**
* 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 public EC key.
*/
private final ECPublicKey publicKey;
/**
* Creates a new Elliptic Curve Diffie-Hellman encrypter.
*
* @param publicKey The public EC key. Must not be {@code null}.
*
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHEncrypter(final ECPublicKey publicKey)
throws JOSEException {
this(publicKey, null);
}
/**
* Creates a new Elliptic Curve Diffie-Hellman encrypter.
*
* @param ecJWK The EC JSON Web Key (JWK). Must not be {@code null}.
*
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHEncrypter(final ECKey ecJWK) throws
JOSEException {
this(ecJWK.toECPublicKey(), null);
}
/**
* Creates a new Elliptic Curve Diffie-Hellman encrypter with an
* optionally specified content encryption key (CEK).
*
* @param publicKey The public EC key. Must not be
* {@code null}.
* @param contentEncryptionKey The content encryption key (CEK) to use.
* If specified its algorithm must be "AES"
* and its length must match the expected
* for the JWE encryption method ("enc").
* If {@code null} a CEK will be generated
* for each JWE.
* @throws JOSEException If the elliptic curve is not supported.
*/
public ECDHEncrypter(final ECPublicKey publicKey, final SecretKey contentEncryptionKey)
throws JOSEException {
super(Curve.forECParameterSpec(publicKey.getParams()), contentEncryptionKey);
this.publicKey = publicKey;
}
/**
* Returns the public EC key.
*
* @return The public EC key.
*/
public ECPublicKey getPublicKey() {
return publicKey;
}
@Override
public Set<Curve> supportedEllipticCurves() {
return SUPPORTED_ELLIPTIC_CURVES;
}
/**
* Encrypts the specified clear 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 clearText The clear text to encrypt. Must not be {@code null}.
*
* @return The resulting JWE crypto parts.
*
* @throws JOSEException If the JWE algorithm or method is not
* supported or if encryption failed for some
* other internal reason.
*/
@Deprecated
public JWECryptoParts encrypt(final JWEHeader header, final byte[] clearText)
throws JOSEException {
return encrypt(header, clearText, AAD.compute(header));
}
@Override
public JWECryptoParts encrypt(final JWEHeader header, final byte[] clearText, final byte[] aad)
throws JOSEException {
// Generate ephemeral EC key pair on the same curve as the consumer's public key
KeyPair ephemeralKeyPair = generateEphemeralKeyPair(publicKey.getParams());
ECPublicKey ephemeralPublicKey = (ECPublicKey)ephemeralKeyPair.getPublic();
ECPrivateKey ephemeralPrivateKey = (ECPrivateKey)ephemeralKeyPair.getPrivate();
// Add the ephemeral public EC key to the header
JWEHeader updatedHeader = new JWEHeader.Builder(header).
ephemeralPublicKey(new ECKey.Builder(getCurve(), ephemeralPublicKey).build()).
build();
// Derive 'Z'
SecretKey Z = ECDH.deriveSharedSecret(
publicKey,
ephemeralPrivateKey,
getJCAContext().getKeyEncryptionProvider());
// for JWEObject we need update the AAD as well
final byte[] updatedAAD = Arrays.equals(AAD.compute(header), aad) ? AAD.compute(updatedHeader) : aad;
return encryptWithZ(updatedHeader, Z, clearText, updatedAAD);
}
/**
* Generates a new ephemeral EC key pair with the specified curve.
*
* @param ecParameterSpec The EC key spec. Must not be {@code null}.
*
* @return The EC key pair.
*
* @throws JOSEException If the EC key pair couldn't be generated.
*/
private KeyPair generateEphemeralKeyPair(final ECParameterSpec ecParameterSpec)
throws JOSEException {
Provider keProvider = getJCAContext().getKeyEncryptionProvider();
try {
KeyPairGenerator generator;
if (keProvider != null) {
generator = KeyPairGenerator.getInstance("EC", keProvider);
} else {
generator = KeyPairGenerator.getInstance("EC");
}
generator.initialize(ecParameterSpec);
return generator.generateKeyPair();
} catch (NoSuchAlgorithmException | InvalidAlgorithmParameterException e) {
throw new JOSEException("Couldn't generate ephemeral EC key pair: " + e.getMessage(), e);
}
}
}