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package org.bouncycastle.crypto.tls;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import java.util.Vector;
import org.bouncycastle.asn1.x509.KeyUsage;
import org.bouncycastle.asn1.x509.SubjectPublicKeyInfo;
import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.DHParameters;
import org.bouncycastle.crypto.params.DHPrivateKeyParameters;
import org.bouncycastle.crypto.params.DHPublicKeyParameters;
import org.bouncycastle.crypto.params.RSAKeyParameters;
import org.bouncycastle.crypto.util.PublicKeyFactory;
/**
* TLS 1.0 PSK key exchange (RFC 4279).
*/
public class TlsPSKKeyExchange
extends AbstractTlsKeyExchange
{
protected TlsPSKIdentity pskIdentity;
protected byte[] psk_identity_hint = null;
protected DHPublicKeyParameters dhAgreeServerPublicKey = null;
protected DHPrivateKeyParameters dhAgreeClientPrivateKey = null;
protected AsymmetricKeyParameter serverPublicKey = null;
protected RSAKeyParameters rsaServerPublicKey = null;
protected byte[] premasterSecret;
public TlsPSKKeyExchange(int keyExchange, Vector supportedSignatureAlgorithms, TlsPSKIdentity pskIdentity)
{
super(keyExchange, supportedSignatureAlgorithms);
switch (keyExchange)
{
case KeyExchangeAlgorithm.PSK:
case KeyExchangeAlgorithm.RSA_PSK:
case KeyExchangeAlgorithm.DHE_PSK:
break;
default:
throw new IllegalArgumentException("unsupported key exchange algorithm");
}
this.pskIdentity = pskIdentity;
}
public void skipServerCredentials()
throws IOException
{
if (keyExchange == KeyExchangeAlgorithm.RSA_PSK)
{
throw new TlsFatalAlert(AlertDescription.unexpected_message);
}
}
public void processServerCertificate(Certificate serverCertificate)
throws IOException
{
if (keyExchange != KeyExchangeAlgorithm.RSA_PSK)
{
throw new TlsFatalAlert(AlertDescription.unexpected_message);
}
if (serverCertificate.isEmpty())
{
throw new TlsFatalAlert(AlertDescription.bad_certificate);
}
org.bouncycastle.asn1.x509.Certificate x509Cert = serverCertificate.getCertificateAt(0);
SubjectPublicKeyInfo keyInfo = x509Cert.getSubjectPublicKeyInfo();
try
{
this.serverPublicKey = PublicKeyFactory.createKey(keyInfo);
}
catch (RuntimeException e)
{
throw new TlsFatalAlert(AlertDescription.unsupported_certificate);
}
// Sanity check the PublicKeyFactory
if (this.serverPublicKey.isPrivate())
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
this.rsaServerPublicKey = validateRSAPublicKey((RSAKeyParameters)this.serverPublicKey);
TlsUtils.validateKeyUsage(x509Cert, KeyUsage.keyEncipherment);
super.processServerCertificate(serverCertificate);
}
public boolean requiresServerKeyExchange()
{
return keyExchange == KeyExchangeAlgorithm.DHE_PSK;
}
public void processServerKeyExchange(InputStream input)
throws IOException
{
this.psk_identity_hint = TlsUtils.readOpaque16(input);
if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
{
byte[] pBytes = TlsUtils.readOpaque16(input);
byte[] gBytes = TlsUtils.readOpaque16(input);
byte[] YsBytes = TlsUtils.readOpaque16(input);
BigInteger p = new BigInteger(1, pBytes);
BigInteger g = new BigInteger(1, gBytes);
BigInteger Ys = new BigInteger(1, YsBytes);
this.dhAgreeServerPublicKey = TlsDHUtils.validateDHPublicKey(new DHPublicKeyParameters(Ys,
new DHParameters(p, g)));
}
}
public void validateCertificateRequest(CertificateRequest certificateRequest)
throws IOException
{
throw new TlsFatalAlert(AlertDescription.unexpected_message);
}
public void processClientCredentials(TlsCredentials clientCredentials)
throws IOException
{
throw new TlsFatalAlert(AlertDescription.internal_error);
}
public void generateClientKeyExchange(OutputStream output)
throws IOException
{
if (psk_identity_hint == null)
{
pskIdentity.skipIdentityHint();
}
else
{
pskIdentity.notifyIdentityHint(psk_identity_hint);
}
byte[] psk_identity = pskIdentity.getPSKIdentity();
TlsUtils.writeOpaque16(psk_identity, output);
if (this.keyExchange == KeyExchangeAlgorithm.RSA_PSK)
{
this.premasterSecret = TlsRSAUtils.generateEncryptedPreMasterSecret(context, this.rsaServerPublicKey,
output);
}
else if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
{
this.dhAgreeClientPrivateKey = TlsDHUtils.generateEphemeralClientKeyExchange(context.getSecureRandom(),
dhAgreeServerPublicKey.getParameters(), output);
}
}
public byte[] generatePremasterSecret()
throws IOException
{
byte[] psk = pskIdentity.getPSK();
byte[] other_secret = generateOtherSecret(psk.length);
ByteArrayOutputStream buf = new ByteArrayOutputStream(4 + other_secret.length + psk.length);
TlsUtils.writeOpaque16(other_secret, buf);
TlsUtils.writeOpaque16(psk, buf);
return buf.toByteArray();
}
protected byte[] generateOtherSecret(int pskLength)
{
if (this.keyExchange == KeyExchangeAlgorithm.DHE_PSK)
{
return TlsDHUtils.calculateDHBasicAgreement(dhAgreeServerPublicKey, dhAgreeClientPrivateKey);
}
if (this.keyExchange == KeyExchangeAlgorithm.RSA_PSK)
{
return this.premasterSecret;
}
return new byte[pskLength];
}
protected RSAKeyParameters validateRSAPublicKey(RSAKeyParameters key)
throws IOException
{
// TODO What is the minimum bit length required?
// key.getModulus().bitLength();
if (!key.getExponent().isProbablePrime(2))
{
throw new TlsFatalAlert(AlertDescription.illegal_parameter);
}
return key;
}
}
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