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package sun.security.ssl;

import java.security.*;
import java.security.interfaces.ECPublicKey;
import java.security.spec.*;

import java.util.EnumSet;
import javax.crypto.SecretKey;
import javax.crypto.KeyAgreement;
import javax.net.ssl.SSLHandshakeException;

Helper class for the ECDH key exchange. It generates the appropriate ephemeral keys as necessary and performs the actual shared secret derivation.
Author: Andreas Sterbenz
Since: 1.6
/** * Helper class for the ECDH key exchange. It generates the appropriate * ephemeral keys as necessary and performs the actual shared secret derivation. * * @since 1.6 * @author Andreas Sterbenz */
final class ECDHCrypt { // our private key private PrivateKey privateKey; // our public key private ECPublicKey publicKey; // Called by ServerHandshaker for static ECDH ECDHCrypt(PrivateKey privateKey, PublicKey publicKey) { this.privateKey = privateKey; this.publicKey = (ECPublicKey)publicKey; } // Called by ServerHandshaker for ephemeral ECDH ECDHCrypt(NamedGroup namedGroup, SecureRandom random) { try { KeyPairGenerator kpg = JsseJce.getKeyPairGenerator("EC"); ECGenParameterSpec params = SupportedGroupsExtension.getECGenParamSpec(namedGroup); kpg.initialize(params, random); KeyPair kp = kpg.generateKeyPair(); privateKey = kp.getPrivate(); publicKey = (ECPublicKey)kp.getPublic(); } catch (GeneralSecurityException e) { throw new RuntimeException("Could not generate ECDH keypair", e); } } // Called by ClientHandshaker with params it received from the server ECDHCrypt(ECParameterSpec params, SecureRandom random) { try { KeyPairGenerator kpg = JsseJce.getKeyPairGenerator("EC"); kpg.initialize(params, random); KeyPair kp = kpg.generateKeyPair(); privateKey = kp.getPrivate(); publicKey = (ECPublicKey)kp.getPublic(); } catch (GeneralSecurityException e) { throw new RuntimeException("Could not generate ECDH keypair", e); } }
Gets the public key of this end of the key exchange.
/** * Gets the public key of this end of the key exchange. */
PublicKey getPublicKey() { return publicKey; } // called by ClientHandshaker with either the server's static or // ephemeral public key SecretKey getAgreedSecret( PublicKey peerPublicKey) throws SSLHandshakeException { try { KeyAgreement ka = JsseJce.getKeyAgreement("ECDH"); ka.init(privateKey); ka.doPhase(peerPublicKey, true); return ka.generateSecret("TlsPremasterSecret"); } catch (GeneralSecurityException e) { throw (SSLHandshakeException) new SSLHandshakeException( "Could not generate secret").initCause(e); } } // called by ServerHandshaker SecretKey getAgreedSecret( byte[] encodedPoint) throws SSLHandshakeException { try { ECParameterSpec params = publicKey.getParams(); ECPoint point = JsseJce.decodePoint(encodedPoint, params.getCurve()); KeyFactory kf = JsseJce.getKeyFactory("EC"); ECPublicKeySpec spec = new ECPublicKeySpec(point, params); PublicKey peerPublicKey = kf.generatePublic(spec); return getAgreedSecret(peerPublicKey); } catch (GeneralSecurityException | java.io.IOException e) { throw (SSLHandshakeException) new SSLHandshakeException( "Could not generate secret").initCause(e); } } // Check constraints of the specified EC public key. void checkConstraints(AlgorithmConstraints constraints, byte[] encodedPoint) throws SSLHandshakeException { try { ECParameterSpec params = publicKey.getParams(); ECPoint point = JsseJce.decodePoint(encodedPoint, params.getCurve()); ECPublicKeySpec spec = new ECPublicKeySpec(point, params); KeyFactory kf = JsseJce.getKeyFactory("EC"); ECPublicKey publicKey = (ECPublicKey)kf.generatePublic(spec); // check constraints of ECPublicKey if (!constraints.permits( EnumSet.of(CryptoPrimitive.KEY_AGREEMENT), publicKey)) { throw new SSLHandshakeException( "ECPublicKey does not comply to algorithm constraints"); } } catch (GeneralSecurityException | java.io.IOException e) { throw (SSLHandshakeException) new SSLHandshakeException( "Could not generate ECPublicKey").initCause(e); } } }