/*
* Copyright (C) 2012-2014 Dominik Schürmann <dominik@dominikschuermann.de>
* Copyright (C) 2010-2014 Thialfihar <thi@thialfihar.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.sufficientlysecure.keychain.pgp;
import org.spongycastle.asn1.DERObjectIdentifier;
import org.spongycastle.asn1.x509.AuthorityKeyIdentifier;
import org.spongycastle.asn1.x509.BasicConstraints;
import org.spongycastle.asn1.x509.GeneralName;
import org.spongycastle.asn1.x509.GeneralNames;
import org.spongycastle.asn1.x509.SubjectKeyIdentifier;
import org.spongycastle.asn1.x509.X509Extensions;
import org.spongycastle.asn1.x509.X509Name;
import org.spongycastle.openpgp.PGPException;
import org.spongycastle.openpgp.PGPPrivateKey;
import org.spongycastle.openpgp.PGPPublicKey;
import org.spongycastle.openpgp.PGPSecretKey;
import org.spongycastle.x509.X509V3CertificateGenerator;
import org.spongycastle.x509.extension.AuthorityKeyIdentifierStructure;
import org.spongycastle.x509.extension.SubjectKeyIdentifierStructure;
import org.sufficientlysecure.keychain.Constants;
import org.sufficientlysecure.keychain.util.Log;
import java.io.IOException;
import java.math.BigInteger;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SignatureException;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import java.text.DateFormat;
import java.util.Date;
import java.util.Iterator;
import java.util.Vector;
import javax.security.auth.callback.Callback;
import javax.security.auth.callback.CallbackHandler;
import javax.security.auth.callback.PasswordCallback;
import javax.security.auth.callback.UnsupportedCallbackException;
public class PgpToX509 {
public static final String DN_COMMON_PART_O = "OpenPGP to X.509 Bridge";
public static final String DN_COMMON_PART_OU = "OpenPGP Keychain cert";
/**
* Creates a self-signed certificate from a public and private key. The (critical) key-usage
* extension is set up with: digital signature, non-repudiation, key-encipherment, key-agreement
* and certificate-signing. The (non-critical) Netscape extension is set up with: SSL client and
* S/MIME. A URI subjectAltName may also be set up.
*
* @param pubKey public key
* @param privKey private key
* @param subject subject (and issuer) DN for this certificate, RFC 2253 format preferred.
* @param startDate date from which the certificate will be valid (defaults to current date and time
* if null)
* @param endDate date until which the certificate will be valid (defaults to current date and time
* if null) *
* @param subjAltNameURI URI to be placed in subjectAltName
* @return self-signed certificate
* @throws InvalidKeyException
* @throws SignatureException
* @throws NoSuchAlgorithmException
* @throws IllegalStateException
* @throws NoSuchProviderException
* @throws CertificateException
* @throws Exception
* @author Bruno Harbulot
*/
public static X509Certificate createSelfSignedCert(
PublicKey pubKey, PrivateKey privKey, X509Name subject, Date startDate, Date endDate,
String subjAltNameURI)
throws InvalidKeyException, IllegalStateException, NoSuchAlgorithmException,
SignatureException, CertificateException, NoSuchProviderException {
X509V3CertificateGenerator certGenerator = new X509V3CertificateGenerator();
certGenerator.reset();
/*
* Sets up the subject distinguished name. Since it's a self-signed certificate, issuer and
* subject are the same.
*/
certGenerator.setIssuerDN(subject);
certGenerator.setSubjectDN(subject);
/*
* Sets up the validity dates.
*/
if (startDate == null) {
startDate = new Date(System.currentTimeMillis());
}
certGenerator.setNotBefore(startDate);
if (endDate == null) {
endDate = new Date(startDate.getTime() + (365L * 24L * 60L * 60L * 1000L));
Log.d(Constants.TAG, "end date is=" + DateFormat.getDateInstance().format(endDate));
}
certGenerator.setNotAfter(endDate);
/*
* The serial-number of this certificate is 1. It makes sense because it's self-signed.
*/
certGenerator.setSerialNumber(BigInteger.ONE);
/*
* Sets the public-key to embed in this certificate.
*/
certGenerator.setPublicKey(pubKey);
/*
* Sets the signature algorithm.
*/
String pubKeyAlgorithm = pubKey.getAlgorithm();
if (pubKeyAlgorithm.equals("DSA")) {
certGenerator.setSignatureAlgorithm("SHA1WithDSA");
} else if (pubKeyAlgorithm.equals("RSA")) {
certGenerator.setSignatureAlgorithm("SHA1WithRSAEncryption");
} else {
RuntimeException re = new RuntimeException("Algorithm not recognised: "
+ pubKeyAlgorithm);
Log.e(Constants.TAG, re.getMessage(), re);
throw re;
}
/*
* Adds the Basic Constraint (CA: true) extension.
*/
certGenerator.addExtension(X509Extensions.BasicConstraints, true,
new BasicConstraints(true));
/*
* Adds the subject key identifier extension.
*/
SubjectKeyIdentifier subjectKeyIdentifier = new SubjectKeyIdentifierStructure(pubKey);
certGenerator
.addExtension(X509Extensions.SubjectKeyIdentifier, false, subjectKeyIdentifier);
/*
* Adds the authority key identifier extension.
*/
AuthorityKeyIdentifier authorityKeyIdentifier = new AuthorityKeyIdentifierStructure(pubKey);
certGenerator.addExtension(X509Extensions.AuthorityKeyIdentifier, false,
authorityKeyIdentifier);
/*
* Adds the subject alternative-name extension.
*/
if (subjAltNameURI != null) {
GeneralNames subjectAltNames = new GeneralNames(new GeneralName(
GeneralName.uniformResourceIdentifier, subjAltNameURI));
certGenerator.addExtension(X509Extensions.SubjectAlternativeName, false,
subjectAltNames);
}
/*
* Creates and sign this certificate with the private key corresponding to the public key of
* the certificate (hence the name "self-signed certificate").
*/
X509Certificate cert = certGenerator.generate(privKey);
/*
* Checks that this certificate has indeed been correctly signed.
*/
cert.verify(pubKey);
return cert;
}
/**
* Creates a self-signed certificate from a PGP Secret Key.
*
* @param pgpSecKey PGP Secret Key (from which one can extract the public and private
* keys and other attributes).
* @param pgpPrivKey PGP Private Key corresponding to the Secret Key (password callbacks
* should be done before calling this method)
* @param subjAltNameURI optional URI to embed in the subject alternative-name
* @return self-signed certificate
* @throws PGPException
* @throws NoSuchProviderException
* @throws InvalidKeyException
* @throws NoSuchAlgorithmException
* @throws SignatureException
* @throws CertificateException
* @author Bruno Harbulot
*/
public static X509Certificate createSelfSignedCert(
PGPSecretKey pgpSecKey, PGPPrivateKey pgpPrivKey, String subjAltNameURI)
throws PGPException, NoSuchProviderException, InvalidKeyException, NoSuchAlgorithmException,
SignatureException, CertificateException {
// get public key from secret key
PGPPublicKey pgpPubKey = pgpSecKey.getPublicKey();
// LOGGER.info("Key ID: " + Long.toHexString(pgpPubKey.getKeyID() & 0xffffffffL));
/*
* The X.509 Name to be the subject DN is prepared. The CN is extracted from the Secret Key
* user ID.
*/
Vector<DERObjectIdentifier> x509NameOids = new Vector<DERObjectIdentifier>();
Vector<String> x509NameValues = new Vector<String>();
x509NameOids.add(X509Name.O);
x509NameValues.add(DN_COMMON_PART_O);
x509NameOids.add(X509Name.OU);
x509NameValues.add(DN_COMMON_PART_OU);
for (@SuppressWarnings("unchecked")
Iterator<Object> it = (Iterator<Object>) pgpSecKey.getUserIDs(); it.hasNext(); ) {
Object attrib = it.next();
x509NameOids.add(X509Name.CN);
x509NameValues.add("CryptoCall");
// x509NameValues.add(attrib.toString());
}
/*
* Currently unused.
*/
Log.d(Constants.TAG, "User attributes: ");
for (@SuppressWarnings("unchecked")
Iterator<Object> it = (Iterator<Object>) pgpSecKey.getUserAttributes(); it.hasNext(); ) {
Object attrib = it.next();
Log.d(Constants.TAG, " - " + attrib + " -- " + attrib.getClass());
}
X509Name x509name = new X509Name(x509NameOids, x509NameValues);
Log.d(Constants.TAG, "Subject DN: " + x509name);
/*
* To check the signature from the certificate on the recipient side, the creation time
* needs to be embedded in the certificate. It seems natural to make this creation time be
* the "not-before" date of the X.509 certificate. Unlimited PGP keys have a validity of 0
* second. In this case, the "not-after" date will be the same as the not-before date. This
* is something that needs to be checked by the service receiving this certificate.
*/
Date creationTime = pgpPubKey.getCreationTime();
Log.d(Constants.TAG,
"pgp pub key creation time=" + DateFormat.getDateInstance().format(creationTime));
Log.d(Constants.TAG, "pgp valid seconds=" + pgpPubKey.getValidSeconds());
Date validTo = null;
if (pgpPubKey.getValidSeconds() > 0) {
validTo = new Date(creationTime.getTime() + 1000L * pgpPubKey.getValidSeconds());
}
X509Certificate selfSignedCert = createSelfSignedCert(
pgpPubKey.getKey(Constants.BOUNCY_CASTLE_PROVIDER_NAME), pgpPrivKey.getKey(),
x509name, creationTime, validTo, subjAltNameURI);
return selfSignedCert;
}
/**
* This is a password callback handler that will fill in a password automatically. Useful to
* configure passwords in advance, but should be used with caution depending on how much you
* allow passwords to be stored within your application.
*
* @author Bruno Harbulot.
*/
public static final class PredefinedPasswordCallbackHandler implements CallbackHandler {
private char[] mPassword;
private String mPrompt;
public PredefinedPasswordCallbackHandler(String password) {
this(password == null ? null : password.toCharArray(), null);
}
public PredefinedPasswordCallbackHandler(char[] password) {
this(password, null);
}
public PredefinedPasswordCallbackHandler(String password, String prompt) {
this(password == null ? null : password.toCharArray(), prompt);
}
public PredefinedPasswordCallbackHandler(char[] password, String prompt) {
this.mPassword = password;
this.mPrompt = prompt;
}
public void handle(Callback[] callbacks) throws IOException, UnsupportedCallbackException {
for (Callback callback : callbacks) {
if (callback instanceof PasswordCallback) {
PasswordCallback pwCallback = (PasswordCallback) callback;
if ((this.mPrompt == null) || (this.mPrompt.equals(pwCallback.getPrompt()))) {
pwCallback.setPassword(this.mPassword);
}
} else {
throw new UnsupportedCallbackException(callback, "Unrecognised callback.");
}
}
}
protected final Object clone() throws CloneNotSupportedException {
throw new CloneNotSupportedException();
}
}
}