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/**
* $RCSfile$
* $Revision: $
* $Date: $
*
* Copyright (C) 2006 Jive Software. All rights reserved.
*
* This software is published under the terms of the GNU Public License (GPL),
* a copy of which is included in this distribution.
*/
package org.jivesoftware.util;
import org.bouncycastle.asn1.*;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.asn1.x509.GeneralNames;
import org.bouncycastle.asn1.x509.X509Extensions;
import org.bouncycastle.asn1.x509.X509Name;
import org.bouncycastle.jce.PKCS10CertificationRequest;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.x509.X509V3CertificateGenerator;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.math.BigInteger;
import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.CertificateParsingException;
import java.security.cert.X509Certificate;
import java.util.*;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* Utility class that provides similar functionality to the keytool tool. Generated certificates
* conform to the XMPP spec where domains are kept in the subject alternative names extension.
*
* @author Gaston Dombiak
*/
public class CertificateManager {
private static Pattern cnPattern = Pattern.compile("(?i)(cn=)([^,]*)");
private static Provider provider = new BouncyCastleProvider();
/**
* The maximum length of lines in certification requests
*/
private static final int CERT_REQ_LINE_LENGTH = 76;
private static List<CertificateEventListener> listeners = new CopyOnWriteArrayList<CertificateEventListener>();
static {
// Add the BC provider to the list of security providers
Security.addProvider(provider);
}
/**
* Creates a new X509 certificate using the DSA algorithm. The new certificate together with its private
* key are stored in the specified key store. However, the key store is not saved to the disk. This means
* that it is up to the "caller" to save the key store to disk after new certificates have been added
* to the store.
*
* @param ksKeys key store where the new certificate and private key are going to be stored.
* @param keyPassword password of the keystore.
* @param alias name to use when storing the certificate in the key store.
* @param issuerDN Issuer string e.g "O=Grid,OU=OGSA,CN=ACME"
* @param subjectDN Subject string e.g "O=Grid,OU=OGSA,CN=John Doe"
* @param domain domain of the server to store in the subject alternative name extension.
* @return the new X509 V3 Certificate.
* @throws GeneralSecurityException
* @throws IOException
*/
public static X509Certificate createDSACert(KeyStore ksKeys, String keyPassword, String alias, String issuerDN,
String subjectDN, String domain)
throws GeneralSecurityException, IOException {
// Generate public and private keys
KeyPair keyPair = generateKeyPair("DSA", 1024);
// Create X509 certificate with keys and specified domain
X509Certificate cert = createX509V3Certificate(keyPair, 60, issuerDN, subjectDN, domain, "SHA1withDSA");
// Store new certificate and private key in the keystore
ksKeys.setKeyEntry(alias, keyPair.getPrivate(), keyPassword.toCharArray(), new X509Certificate[]{cert});
// Notify listeners that a new certificate has been created
for (CertificateEventListener listener : listeners) {
try {
listener.certificateCreated(ksKeys, alias, cert);
}
catch (Exception e) {
Log.error(e);
}
}
// Return new certificate
return cert;
}
/**
* Creates a new X509 certificate using the RSA algorithm. The new certificate together with its private
* key are stored in the specified key store. However, the key store is not saved to the disk. This means
* that it is up to the "caller" to save the key store to disk after new certificates have been added
* to the store.
*
* @param ksKeys key store where the new certificate and private key are going to be stored.
* @param keyPassword password of the keystore.
* @param alias name to use when storing the certificate in the key store.
* @param issuerDN Issuer string e.g "O=Grid,OU=OGSA,CN=ACME"
* @param subjectDN Subject string e.g "O=Grid,OU=OGSA,CN=John Doe"
* @param domain domain of the server to store in the subject alternative name extension.
* @return the new X509 V3 Certificate.
* @throws GeneralSecurityException
* @throws IOException
*/
public static X509Certificate createRSACert(KeyStore ksKeys, String keyPassword, String alias, String issuerDN,
String subjectDN, String domain)
throws GeneralSecurityException, IOException {
// Generate public and private keys
KeyPair keyPair = generateKeyPair("RSA", 1024);
// Create X509 certificate with keys and specified domain
X509Certificate cert = createX509V3Certificate(keyPair, 60, issuerDN, subjectDN, domain, "MD5withRSA");
// Store new certificate and private key in the keystore
ksKeys.setKeyEntry(alias, keyPair.getPrivate(), keyPassword.toCharArray(), new X509Certificate[]{cert});
// Notify listeners that a new certificate has been created
for (CertificateEventListener listener : listeners) {
try {
listener.certificateCreated(ksKeys, alias, cert);
}
catch (Exception e) {
Log.error(e);
}
}
// Return new certificate
return cert;
}
/**
* Deletes the specified certificate from the
*
* @param ksKeys key store where the certificate is stored.
* @param alias alias of the certificate to delete.
* @throws GeneralSecurityException
* @throws IOException
*/
public static void deleteCertificate(KeyStore ksKeys, String alias) throws GeneralSecurityException, IOException {
ksKeys.deleteEntry(alias);
// Notify listeners that a new certificate has been created
for (CertificateEventListener listener : listeners) {
try {
listener.certificateDeleted(ksKeys, alias);
}
catch (Exception e) {
Log.error(e);
}
}
}
/**
* Returns the identities of the remote server as defined in the specified certificate. The
* identities are defined in the subjectDN of the certificate and it can also be defined in
* the subjectAltName extensions of type "xmpp". When the extension is being used then the
* identities defined in the extension are going to be returned. Otherwise, the value stored in
* the subjectDN is returned.
*
* @param x509Certificate the certificate the holds the identities of the remote server.
* @return the identities of the remote server as defined in the specified certificate.
*/
public static List<String> getPeerIdentities(X509Certificate x509Certificate) {
// Look the identity in the subjectAltName extension if available
List<String> names = getSubjectAlternativeNames(x509Certificate);
if (names.isEmpty()) {
String name = x509Certificate.getSubjectDN().getName();
Matcher matcher = cnPattern.matcher(name);
if (matcher.find()) {
name = matcher.group(2);
}
// Create an array with the unique identity
names = new ArrayList<String>();
names.add(name);
}
return names;
}
/**
* Returns the JID representation of an XMPP entity contained as a SubjectAltName extension
* in the certificate. If none was found then return <tt>null</tt>.
*
* @param certificate the certificate presented by the remote entity.
* @return the JID representation of an XMPP entity contained as a SubjectAltName extension
* in the certificate. If none was found then return <tt>null</tt>.
*/
private static List<String> getSubjectAlternativeNames(X509Certificate certificate) {
List<String> identities = new ArrayList<String>();
try {
Collection<List<?>> altNames = certificate.getSubjectAlternativeNames();
// Check that the certificate includes the SubjectAltName extension
if (altNames == null) {
return Collections.emptyList();
}
// Use the type OtherName to search for the certified server name
for (List item : altNames) {
Integer type = (Integer) item.get(0);
if (type == 0) {
// Type OtherName found so return the associated value
try {
// Value is encoded using ASN.1 so decode it to get the server's identity
ASN1InputStream decoder = new ASN1InputStream((byte[]) item.toArray()[1]);
DEREncodable encoded = decoder.readObject();
encoded = ((DERSequence) encoded).getObjectAt(1);
encoded = ((DERTaggedObject) encoded).getObject();
encoded = ((DERTaggedObject) encoded).getObject();
String identity = ((DERUTF8String) encoded).getString();
// Add the decoded server name to the list of identities
identities.add(identity);
}
catch (UnsupportedEncodingException e) {
// Ignore
}
catch (IOException e) {
// Ignore
}
catch (Exception e) {
Log.error("Error decoding subjectAltName", e);
}
}
// Other types are not good for XMPP so ignore them
if (Log.isDebugEnabled()) {
Log.debug("SubjectAltName of invalid type found: " + certificate);
}
}
}
catch (CertificateParsingException e) {
Log.error("Error parsing SubjectAltName in certificate: " + certificate, e);
}
return identities;
}
/**
* Returns true if an RSA certificate was found in the specified keystore for the specified domain.
*
* @param ksKeys the keystore that contains the certificates.
* @param domain domain of the server signed by the certificate.
* @return true if an RSA certificate was found in the specified keystore for the specified domain.
* @throws KeyStoreException
*/
public static boolean isRSACertificate(KeyStore ksKeys, String domain) throws KeyStoreException {
return isCertificate(ksKeys, domain, "RSA");
}
/**
* Returns true if an DSA certificate was found in the specified keystore for the specified domain.
*
* @param ksKeys the keystore that contains the certificates.
* @param domain domain of the server signed by the certificate.
* @return true if an DSA certificate was found in the specified keystore for the specified domain.
* @throws KeyStoreException
*/
public static boolean isDSACertificate(KeyStore ksKeys, String domain) throws KeyStoreException {
return isCertificate(ksKeys, domain, "DSA");
}
/**
* Returns true if the specified certificate is using the DSA algorithm. The DSA algorithm is not
* good for encryption but only for authentication. On the other hand, the RSA algorithm is good
* for encryption and authentication.
*
* @param certificate the certificate to analyze.
* @return true if the specified certificate is using the DSA algorithm.
* @throws KeyStoreException
*/
public static boolean isDSACertificate(X509Certificate certificate) throws KeyStoreException {
return certificate.getPublicKey().getAlgorithm().equals("DSA");
}
/**
* Returns true if a certificate with the specifed configuration was found in the key store.
*
* @param ksKeys the keystore to use for searching the certificate.
* @param domain the domain present in the subjectAltName.
* @param algorithm the DSA or RSA algorithm used by the certificate.
* @return true if a certificate with the specifed configuration was found in the key store.
* @throws KeyStoreException
*/
private static boolean isCertificate(KeyStore ksKeys, String domain, String algorithm) throws KeyStoreException {
for (Enumeration<String> aliases = ksKeys.aliases(); aliases.hasMoreElements();) {
X509Certificate certificate = (X509Certificate) ksKeys.getCertificate(aliases.nextElement());
for (String identity : getPeerIdentities(certificate)) {
if (identity.endsWith(domain) && certificate.getPublicKey().getAlgorithm().equals(algorithm)) {
return true;
}
}
}
return false;
}
/**
* Creates and returns the content of a new singing request for the specified certificate. Signing
* requests are required by Certificate Authorities as part of their signing process. The signing request
* contains information about the certificate issuer, subject DN, subject alternative names and public key.
* Private keys are not included. After the Certificate Authority verified and signed the certificate a new
* certificate is going to be returned. Use {@link #installReply(java.security.KeyStore, java.security.KeyStore, String, String, java.io.InputStream, boolean, boolean)}
* to import the CA reply.
*
* @param cert the certificate to create a signing request.
* @param privKey the private key of the certificate.
* @return the content of a new singing request for the specified certificate.
* @throws Exception
*/
public static String createSigningRequest(X509Certificate cert, PrivateKey privKey) throws Exception {
StringBuilder sb = new StringBuilder();
String subject = cert.getSubjectDN().getName();
X509Name xname = new X509Name(subject);
PublicKey pubKey = cert.getPublicKey();
String signatureAlgorithm = "DSA".equals(pubKey.getAlgorithm()) ? "SHA1withDSA" : "MD5withRSA";
PKCS10CertificationRequest csr =
new PKCS10CertificationRequest(signatureAlgorithm, xname, pubKey, null, privKey);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
DEROutputStream deros = new DEROutputStream(baos);
deros.writeObject(csr.getDERObject());
String sTmp = new String(org.bouncycastle.util.encoders.Base64.encode(baos.toByteArray()));
// Header
sb.append("-----BEGIN NEW CERTIFICATE REQUEST-----\n");
// Add signing request content (base 64 encoded)
for (int iCnt = 0; iCnt < sTmp.length(); iCnt += CERT_REQ_LINE_LENGTH) {
int iLineLength;
if ((iCnt + CERT_REQ_LINE_LENGTH) > sTmp.length()) {
iLineLength = sTmp.length() - iCnt;
} else {
iLineLength = CERT_REQ_LINE_LENGTH;
}
sb.append(sTmp.substring(iCnt, iCnt + iLineLength)).append("\n");
}
// Footer
sb.append("-----END NEW CERTIFICATE REQUEST-----\n");
return sb.toString();
}
/**
* Installs the Certificate Authority reply returned as part of the signing request. The certificate
* being signed will get its certificate chain updated with the imported certificate(s). An exception
* will be thrown if the replied certificate does not match a local certificate or if the signing
* authority is not known by the server (i.e. keystore and truststore files). When <tt>trustCACerts</tt>
* is set to <tt>true</tt> then certificates present in the truststore file will be used to verify the
* identity of the entity signing the certificate. In case the reply is composed of more than one
* certificate then you can also specify if you want to verify that the root certificate in the chain
* can be trusted.
*
* @param keyStore key store where the certificate is stored.
* @param trustStore key store where ca certificates are stored.
* @param keyPassword password of the keystore.
* @param alias the alias of the existing certificate being signed.
* @param inputStream the stream containing the CA reply.
* @param trustCACerts true if certificates present in the truststore file will be used to verify the
* identity of the entity signing the certificate.
* @param validateRoot true if you want to verify that the root certificate in the chain can be trusted
* based on the truststore.
* @return true if the CA reply was successfully processed.
* @throws Exception
*/
public static boolean installReply(KeyStore keyStore, KeyStore trustStore, String keyPassword, String alias, InputStream inputStream, boolean trustCACerts,
boolean validateRoot) throws Exception {
// Check that there is a certificate for the specified alias
X509Certificate certificate = (X509Certificate) keyStore.getCertificate(alias);
if (certificate == null) {
Log.warn("Certificate not found for alias: " + alias);
return false;
}
// Retrieve the private key of the stored certificate
PrivateKey privKey = (PrivateKey) keyStore.getKey(alias, keyPassword.toCharArray());
// Load certificates found in the PEM input stream
List<X509Certificate> certs = new ArrayList<X509Certificate>();
for (Certificate cert : CertificateFactory.getInstance("X509").generateCertificates(inputStream)) {
certs.add((X509Certificate) cert);
}
if (certs.isEmpty()) {
throw new Exception("Reply has no certificates");
}
List<X509Certificate> newCerts;
if (certs.size() == 1) {
// Reply has only one certificate
newCerts = establishCertChain(keyStore, trustStore, certificate, certs.get(0), trustCACerts);
} else {
// Reply has a chain of certificates
newCerts = validateReply(keyStore, trustStore, alias, certificate, certs, trustCACerts, validateRoot);
}
if (newCerts != null) {
keyStore.setKeyEntry(alias, privKey, keyPassword.toCharArray(),
newCerts.toArray(new X509Certificate[newCerts.size()]));
// Notify listeners that a new certificate has been created
for (CertificateEventListener listener : listeners) {
try {
listener.certificateSigned(keyStore, alias, newCerts);
}
catch (Exception e) {
Log.error(e);
}
}
return true;
} else {
return false;
}
}
/**
* Registers a listener to receive events.
*
* @param listener the listener.
*/
public static void addListener(CertificateEventListener listener) {
if (listener == null) {
throw new NullPointerException();
}
listeners.add(listener);
}
/**
* Unregisters a listener to receive events.
*
* @param listener the listener.
*/
public static void removeListener(CertificateEventListener listener) {
listeners.remove(listener);
}
private static List<X509Certificate> establishCertChain(KeyStore keyStore, KeyStore trustStore,
X509Certificate certificate,
X509Certificate certReply, boolean trustCACerts)
throws Exception {
if (certificate != null) {
PublicKey publickey = certificate.getPublicKey();
PublicKey publickey1 = certReply.getPublicKey();
if (!publickey.equals(publickey1)) {
throw new Exception("Public keys in reply and keystore don't match");
}
if (certReply.equals(certificate)) {
throw new Exception("Certificate reply and certificate in keystore are identical");
}
}
Map<Principal, List<X509Certificate>> knownCerts = new Hashtable<Principal, List<X509Certificate>>();
if (keyStore.size() > 0) {
knownCerts.putAll(getCertsByIssuer(keyStore));
}
if (trustCACerts && trustStore.size() > 0) {
knownCerts.putAll(getCertsByIssuer(trustStore));
}
LinkedList<X509Certificate> answer = new LinkedList<X509Certificate>();
if (buildChain(certReply, answer, knownCerts)) {
return answer;
} else {
throw new Exception("Failed to establish chain from reply");
}
}
/**
* Builds the certificate chain of the specified certificate based on the known list of certificates
* that were issued by their respective Principals. Returns true if the entire chain of all certificates
* was successfully built.
*
* @param certificate certificate to build its chain.
* @param answer the certificate chain for the corresponding certificate.
* @param knownCerts list of known certificates grouped by their issues (i.e. Principals).
* @return true if the entire chain of all certificates was successfully built.
*/
private static boolean buildChain(X509Certificate certificate, LinkedList<X509Certificate> answer,
Map<Principal, List<X509Certificate>> knownCerts) {
Principal subject = certificate.getSubjectDN();
Principal issuer = certificate.getIssuerDN();
// Check if the certificate is a root certificate (i.e. was issued by the same Principal that
// is present in the subject)
if (subject.equals(issuer)) {
answer.addFirst(certificate);
return true;
}
// Get the list of known certificates of the certificate's issuer
List<X509Certificate> issuerCerts = knownCerts.get(issuer);
if (issuerCerts == null || issuerCerts.isEmpty()) {
// No certificates were found so building of chain failed
return false;
}
for (X509Certificate issuerCert : issuerCerts) {
PublicKey publickey = issuerCert.getPublicKey();
try {
// Verify the certificate with the specified public key
certificate.verify(publickey);
// Certificate was verified successfully so build chain of issuer's certificate
if (!buildChain(issuerCert, answer, knownCerts)) {
return false;
}
}
catch (Exception exception) {
// Failed to verify certificate
return false;
}
}
answer.addFirst(certificate);
return true;
}
/**
* Returns a Map where the key holds the certificate issuers and values the certificates of each issuer.
*
* @param ks the keystore to get its certs per issuer.
* @return a map with the certificates per issuer.
* @throws Exception
*/
private static Map<Principal, List<X509Certificate>> getCertsByIssuer(KeyStore ks)
throws Exception {
Map<Principal, List<X509Certificate>> answer = new HashMap<Principal, List<X509Certificate>>();
Enumeration<String> aliases = ks.aliases();
while (aliases.hasMoreElements()) {
String alias = aliases.nextElement();
X509Certificate cert = (X509Certificate) ks.getCertificate(alias);
if (cert != null) {
Principal subjectDN = cert.getSubjectDN();
List<X509Certificate> vec = answer.get(subjectDN);
if (vec == null) {
vec = new ArrayList<X509Certificate>();
vec.add(cert);
}
else {
if (!vec.contains(cert)) {
vec.add(cert);
}
}
answer.put(subjectDN, vec);
}
}
return answer;
}
/**
* Validates chain in certification reply, and returns the ordered
* elements of the chain (with user certificate first, and root
* certificate last in the array).
*
* @param alias the alias name
* @param userCert the user certificate of the alias
* @param replyCerts the chain provided in the reply
*/
private static List<X509Certificate> validateReply(KeyStore keyStore, KeyStore trustStore, String alias,
X509Certificate userCert, List<X509Certificate> replyCerts,
boolean trustCACerts, boolean verifyRoot)
throws Exception {
// order the certs in the reply (bottom-up).
int i;
PublicKey userPubKey = userCert.getPublicKey();
for (i = 0; i < replyCerts.size(); i++) {
if (userPubKey.equals(replyCerts.get(i).getPublicKey())) {
break;
}
}
if (i == replyCerts.size()) {
throw new Exception(
"Certificate reply does not contain public key for <alias>: " + alias);
}
X509Certificate tmpCert = replyCerts.get(0);
replyCerts.set(0, replyCerts.get(i));
replyCerts.set(i, tmpCert);
Principal issuer = replyCerts.get(0).getIssuerDN();
for (i = 1; i < replyCerts.size() - 1; i++) {
// find a cert in the reply whose "subject" is the same as the
// given "issuer"
int j;
for (j = i; j < replyCerts.size(); j++) {
Principal subject = replyCerts.get(j).getSubjectDN();
if (subject.equals(issuer)) {
tmpCert = replyCerts.get(i);
replyCerts.set(i, replyCerts.get(j));
replyCerts.set(j, tmpCert);
issuer = replyCerts.get(i).getIssuerDN();
break;
}
}
if (j == replyCerts.size()) {
throw new Exception("Incomplete certificate chain in reply");
}
}
// now verify each cert in the ordered chain
for (i = 0; i < replyCerts.size() - 1; i++) {
PublicKey pubKey = replyCerts.get(i + 1).getPublicKey();
try {
replyCerts.get(i).verify(pubKey);
}
catch (Exception e) {
throw new Exception(
"Certificate chain in reply does not verify: " + e.getMessage());
}
}
if (!verifyRoot) {
return replyCerts;
}
// do we trust the (root) cert at the top?
X509Certificate topCert = replyCerts.get(replyCerts.size() - 1);
boolean foundInKeyStore = keyStore.getCertificateAlias(topCert) != null;
boolean foundInCAStore = trustCACerts && (trustStore.getCertificateAlias(topCert) != null);
if (!foundInKeyStore && !foundInCAStore) {
boolean verified = false;
X509Certificate rootCert = null;
if (trustCACerts) {
for (Enumeration<String> aliases = trustStore.aliases(); aliases.hasMoreElements();) {
String name = aliases.nextElement();
rootCert = (X509Certificate) trustStore.getCertificate(name);
if (rootCert != null) {
try {
topCert.verify(rootCert.getPublicKey());
verified = true;
break;
}
catch (Exception e) {
// Ignore
}
}
}
}
if (!verified) {
return null;
}
else {
// Check if the cert is a self-signed cert
if (!topCert.getSubjectDN().equals(topCert.getIssuerDN())) {
// append the (self-signed) root CA cert to the chain
replyCerts.add(rootCert);
}
}
}
return replyCerts;
}
/**
* Creates an X509 version3 certificate.
*
* @param kp KeyPair that keeps the public and private keys for the new certificate.
* @param months time to live
* @param issuerDN Issuer string e.g "O=Grid,OU=OGSA,CN=ACME"
* @param subjectDN Subject string e.g "O=Grid,OU=OGSA,CN=John Doe"
* @param domain Domain of the server.
* @param signAlgoritm Signature algorithm. This can be either a name or an OID.
* @return X509 V3 Certificate
* @throws GeneralSecurityException
* @throws IOException
*/
private static synchronized X509Certificate createX509V3Certificate(KeyPair kp, int months, String issuerDN,
String subjectDN, String domain,
String signAlgoritm)
throws GeneralSecurityException, IOException {
PublicKey pubKey = kp.getPublic();
PrivateKey privKey = kp.getPrivate();
byte[] serno = new byte[8];
SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
random.setSeed((new Date().getTime()));
random.nextBytes(serno);
BigInteger serial = (new java.math.BigInteger(serno)).abs();
X509V3CertificateGenerator certGenerator = new X509V3CertificateGenerator();
certGenerator.reset();
certGenerator.setSerialNumber(serial);
certGenerator.setIssuerDN(new X509Name(issuerDN));
certGenerator.setNotBefore(new Date(System.currentTimeMillis()));
certGenerator.setNotAfter(
new Date(System.currentTimeMillis() + months * (1000L * 60 * 60 * 24 * 30)));
certGenerator.setSubjectDN(new X509Name(subjectDN));
certGenerator.setPublicKey(pubKey);
certGenerator.setSignatureAlgorithm(signAlgoritm);
// Generate the subject alternative name
boolean critical = subjectDN == null || "".equals(subjectDN.trim());
DERSequence othernameSequence = new DERSequence(new ASN1Encodable[]{
new DERObjectIdentifier("1.3.6.1.5.5.7.8.5"), new DERTaggedObject(true, 0, new DERUTF8String(domain))});
GeneralName othernameGN = new GeneralName(GeneralName.otherName, othernameSequence);
GeneralNames subjectAltNames = new GeneralNames(new DERSequence(new ASN1Encodable[]{othernameGN}));
// Add subject alternative name extension
certGenerator.addExtension(X509Extensions.SubjectAlternativeName, critical, subjectAltNames);
X509Certificate cert =
certGenerator.generateX509Certificate(privKey, "BC", new SecureRandom());
cert.checkValidity(new Date());
cert.verify(pubKey);
return cert;
}
/**
* Returns a new public & private key with the specified algorithm (e.g. DSA, RSA, etc.).
*
* @param algorithm DSA, RSA, etc.
* @param keysize the keysize. This is an algorithm-specific metric, such as modulus
* length, specified in number of bits.
* @return a new public & private key with the specified algorithm (e.g. DSA, RSA, etc.).
* @throws GeneralSecurityException
*/
private static KeyPair generateKeyPair(String algorithm, int keysize) throws GeneralSecurityException {
KeyPairGenerator generator;
if (provider == null) {
generator = KeyPairGenerator.getInstance(algorithm);
} else {
generator = KeyPairGenerator.getInstance(algorithm, provider);
}
generator.initialize(keysize, new SecureRandom());
return generator.generateKeyPair();
}
}