Java tutorial
/* * Copyright 2004 - 2013 Wayne Grant * 2013 - 2016 Kai Kramer * * This file is part of KeyStore Explorer. * * KeyStore Explorer 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. * * KeyStore Explorer 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 KeyStore Explorer. If not, see <http://www.gnu.org/licenses/>. */ package net.sf.keystore_explorer.crypto.x509; import static net.sf.keystore_explorer.crypto.SecurityProvider.BOUNCY_CASTLE; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStream; import java.security.InvalidKeyException; import java.security.KeyStore; import java.security.KeyStoreException; import java.security.NoSuchAlgorithmException; import java.security.NoSuchProviderException; import java.security.SignatureException; import java.security.cert.CRLException; import java.security.cert.CertPath; import java.security.cert.Certificate; import java.security.cert.CertificateException; import java.security.cert.CertificateFactory; import java.security.cert.X509CRL; import java.security.cert.X509Certificate; import java.text.MessageFormat; import java.util.ArrayList; import java.util.Collection; import java.util.Collections; import java.util.Enumeration; import java.util.Iterator; import java.util.List; import java.util.ResourceBundle; import javax.security.auth.x500.X500Principal; import org.apache.commons.io.IOUtils; import org.bouncycastle.asn1.ASN1InputStream; import org.bouncycastle.asn1.ASN1Sequence; import org.bouncycastle.asn1.x500.AttributeTypeAndValue; import org.bouncycastle.asn1.x500.RDN; import org.bouncycastle.asn1.x500.X500Name; import org.bouncycastle.asn1.x500.style.BCStyle; import org.bouncycastle.asn1.x509.X509CertificateStructure; import org.bouncycastle.util.encoders.Base64; import com.haitai.jsse.provider.OriginalFile; import net.sf.keystore_explorer.crypto.CryptoException; import net.sf.keystore_explorer.crypto.signing.SignatureType; import net.sf.keystore_explorer.utilities.ArrayUtils; import net.sf.keystore_explorer.utilities.io.ReadUtil; import net.sf.keystore_explorer.utilities.pem.PemInfo; import net.sf.keystore_explorer.utilities.pem.PemUtil; /** * Provides utility methods relating to X509 Certificates and CRLs. * */ public final class X509CertUtil { private static ResourceBundle res = ResourceBundle.getBundle("net/sf/keystore_explorer/crypto/x509/resources"); private static final String X509_CERT_TYPE = "X.509"; private static final String PKCS7_ENCODING = "PKCS7"; private static final String PKI_PATH_ENCODING = "PkiPath"; private static final String CERT_PEM_TYPE = "CERTIFICATE"; private static final String PKCS7_PEM_TYPE = "PKCS7"; public static final String BEGIN_CERTIFICATE = "-----BEGIN CERTIFICATE-----"; public static final String END_CERTIFICATE = "-----END CERTIFICATE-----"; public static final String BASE64_TESTER = "^([A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{4}|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{2}==)$"; private X509CertUtil() { } /** * Load one or more certificates from the specified stream. * * @param is * Stream to load certificates from * @return The certificates * @throws CryptoException * Problem encountered while loading the certificate(s) */ public static X509Certificate[] loadCertificates(InputStream is) throws CryptoException { byte[] certsBytes = null; try { certsBytes = ReadUtil.readFully(is); // fix common input certificate problems by converting PEM/B64 to DER certsBytes = fixCommonInputCertProblems(certsBytes); is = new ByteArrayInputStream(certsBytes); CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE, "GNU-PKI"); Collection<? extends Certificate> certs = cf.generateCertificates(is); ArrayList<X509Certificate> loadedCerts = new ArrayList<X509Certificate>(); for (Iterator<? extends Certificate> itr = certs.iterator(); itr.hasNext();) { X509Certificate cert = (X509Certificate) itr.next(); if (cert != null) { loadedCerts.add(cert); } } return loadedCerts.toArray(new X509Certificate[loadedCerts.size()]); } catch (IOException ex) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), ex); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), e); } catch (CertificateException ex) { // Failed to load certificates, may be pki path encoded - try loading as that try { return loadCertificatesPkiPath(new ByteArrayInputStream(certsBytes)); } catch (CryptoException ex2) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), ex); } } finally { IOUtils.closeQuietly(is); } } public static X509Certificate[] loadCertificates(InputStream is, String keyStoreType) throws CryptoException { byte[] certsBytes = null; CertificateFactory cf = null; try { certsBytes = ReadUtil.readFully(is); // fix common input certificate problems by converting PEM/B64 to DER certsBytes = fixCommonInputCertProblems(certsBytes); is = new ByteArrayInputStream(certsBytes); if (keyStoreType.equals("HTKS")) { cf = CertificateFactory.getInstance(X509_CERT_TYPE, "GNU-PKI"); } else { cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); } Collection<? extends Certificate> certs = cf.generateCertificates(is); ArrayList<X509Certificate> loadedCerts = new ArrayList<X509Certificate>(); for (Iterator<? extends Certificate> itr = certs.iterator(); itr.hasNext();) { X509Certificate cert = (X509Certificate) itr.next(); if (cert != null) { loadedCerts.add(cert); } } return loadedCerts.toArray(new X509Certificate[loadedCerts.size()]); } catch (IOException ex) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), ex); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), e); } catch (CertificateException ex) { // Failed to load certificates, may be pki path encoded - try loading as that try { return loadCertificatesPkiPath(new ByteArrayInputStream(certsBytes)); } catch (CryptoException ex2) { throw new CryptoException(res.getString("NoLoadCertificate.exception.message"), ex); } } finally { IOUtils.closeQuietly(is); } } private static X509Certificate[] loadCertificatesPkiPath(InputStream is) throws CryptoException { try { CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); CertPath certPath = cf.generateCertPath(is, PKI_PATH_ENCODING); List<? extends Certificate> certs = certPath.getCertificates(); ArrayList<X509Certificate> loadedCerts = new ArrayList<X509Certificate>(); for (Iterator<? extends Certificate> itr = certs.iterator(); itr.hasNext();) { X509Certificate cert = (X509Certificate) itr.next(); if (cert != null) { loadedCerts.add(cert); } } return loadedCerts.toArray(new X509Certificate[loadedCerts.size()]); } catch (CertificateException e) { throw new CryptoException(res.getString("NoLoadPkiPath.exception.message"), e); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoLoadPkiPath.exception.message"), e); } finally { IOUtils.closeQuietly(is); } } private static byte[] fixCommonInputCertProblems(byte[] certs) throws IOException { // remove PEM header/footer String certsStr = new String(certs); if (certsStr.startsWith(BEGIN_CERTIFICATE)) { certsStr = certsStr.replaceAll(BEGIN_CERTIFICATE, ""); certsStr = certsStr.replaceAll(END_CERTIFICATE, "!"); } // If one or more base 64 encoded certs then decode String[] splitCertsStr = certsStr.split("!"); byte[] allDecoded = null; for (String singleCertB64 : splitCertsStr) { byte[] decoded = attemptBase64Decode(singleCertB64.trim()); if (decoded != null) { allDecoded = ArrayUtils.add(allDecoded, decoded); } } if (allDecoded != null) { return allDecoded; } return certs; } private static byte[] attemptBase64Decode(String toTest) { // Attempt to decode the supplied byte array as a base 64 encoded SPC. // Character set may be UTF-16 big endian or ASCII. char[] base64 = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/', '=' }; // remove all non visible characters (like newlines) and whitespace toTest = toTest.replaceAll("\\s", ""); // Check all characters are base 64. Discard any zero bytes that be // present if UTF-16 encoding is used but will mess up a base 64 decode StringBuffer sb = new StringBuffer(); nextChar: for (int i = 0; i < toTest.length(); i++) { char c = toTest.charAt(i); for (int j = 0; j < base64.length; j++) { // append base 64 byte if (c == base64[j]) { sb.append(c); continue nextChar; } else if (c == 0) { // discard zero byte continue nextChar; } } // not base 64 return null; } // use BC for actual decoding try { return Base64.decode(sb.toString()); } catch (Exception e) { // not base 64 } return null; } /** * Load a CRL from the specified stream. * * @param is * Stream to load CRL from * @return The CRL * @throws CryptoException * Problem encountered while loading the CRL */ public static X509CRL loadCRL(InputStream is) throws CryptoException { try { CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE); X509CRL crl = (X509CRL) cf.generateCRL(is); return crl; } catch (CertificateException ex) { throw new CryptoException(res.getString("NoLoadCrl.exception.message"), ex); } catch (CRLException ex) { throw new CryptoException(res.getString("NoLoadCrl.exception.message"), ex); } finally { IOUtils.closeQuietly(is); } } /** * Convert the supplied array of certificate objects into X509Certificate * objects. * * @param certsIn * The Certificate objects * @return The converted X509Certificate objects * @throws CryptoException * A problem occurred during the conversion */ public static X509Certificate[] convertCertificates(Certificate[] certsIn) throws CryptoException { if (certsIn == null) { return new X509Certificate[0]; } X509Certificate[] certsOut = new X509Certificate[certsIn.length]; for (int i = 0; i < certsIn.length; i++) { certsOut[i] = convertCertificate(certsIn[i]); } return certsOut; } /** * Convert the supplied certificate object into an X509Certificate object. * * @param certIn * The Certificate object * @return The converted X509Certificate object * @throws CryptoException * A problem occurred during the conversion */ public static X509Certificate convertCertificate(Certificate certIn) throws CryptoException { try { CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); ByteArrayInputStream bais = new ByteArrayInputStream(certIn.getEncoded()); return (X509Certificate) cf.generateCertificate(bais); } catch (CertificateException e) { throw new CryptoException(res.getString("NoConvertCertificate.exception.message"), e); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoConvertCertificate.exception.message"), e); } } public static X509Certificate convertCertificate(Certificate certIn, String keyStoreType) throws CryptoException { try { CertificateFactory cf = null; if (keyStoreType.equals("HTKS")) { cf = CertificateFactory.getInstance(X509_CERT_TYPE, "GNU-PKI"); } else { cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); } ByteArrayInputStream bais = new ByteArrayInputStream(certIn.getEncoded()); return (X509Certificate) cf.generateCertificate(bais); } catch (CertificateException e) { throw new CryptoException(res.getString("NoConvertCertificate.exception.message"), e); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoConvertCertificate.exception.message"), e); } } /** * Order the supplied array of X.509 certificates in issued to issuer order. * * @param certs * X.509 certificates * @return The ordered X.509 certificates */ public static X509Certificate[] orderX509CertChain(X509Certificate certs[]) { if (certs == null) { return new X509Certificate[0]; } if (certs.length <= 1) { return certs; } // Put together each possible certificate path... ArrayList<ArrayList<X509Certificate>> paths = new ArrayList<ArrayList<X509Certificate>>(); // For each possible path... for (int i = 0; i < certs.length; i++) { // Each possible path assumes a different certificate is the root issuer ArrayList<X509Certificate> path = new ArrayList<X509Certificate>(); X509Certificate issuerCert = certs[i]; path.add(issuerCert); X509Certificate newIssuer = null; // Recursively build that path by finding the next issued certificate while ((newIssuer = findIssuedCert(issuerCert, certs)) != null) { // Found an issued cert, now attempt to find its issued certificate issuerCert = newIssuer; path.add(0, newIssuer); } // Path complete paths.add(path); } // Get longest path - this will be the ordered path ArrayList<X509Certificate> longestPath = paths.get(0); for (int i = 1; i < paths.size(); i++) { ArrayList<X509Certificate> path = paths.get(i); if (path.size() > longestPath.size()) { longestPath = path; } } // Return longest path return longestPath.toArray(new X509Certificate[longestPath.size()]); } private static X509Certificate findIssuedCert(X509Certificate issuerCert, X509Certificate[] certs) { // Find a certificate issued by the supplied certificate based on distiguished name for (int i = 0; i < certs.length; i++) { X509Certificate cert = certs[i]; if (issuerCert.getSubjectX500Principal().equals(cert.getSubjectX500Principal()) && issuerCert.getIssuerX500Principal().equals(cert.getIssuerX500Principal())) { // Checked certificate is issuer - ignore it continue; } if (issuerCert.getSubjectX500Principal().equals(cert.getIssuerX500Principal())) { return cert; } } return null; } /** * X.509 encode a certificate. * * @return The encoding * @param cert * The certificate * @throws CryptoException * If there was a problem encoding the certificate */ public static byte[] getCertEncodedX509(X509Certificate cert) throws CryptoException { try { return cert.getEncoded(); } catch (CertificateException ex) { throw new CryptoException(res.getString("NoDerEncodeCertificate.exception.message"), ex); } } /** * X.509 encode a certificate and PEM the encoding. * * @return The PEM'd encoding * @param cert * The certificate * @throws CryptoException * If there was a problem encoding the certificate */ public static String getCertEncodedX509Pem(X509Certificate cert) throws CryptoException { PemInfo pemInfo = new PemInfo(CERT_PEM_TYPE, null, getCertEncodedX509(cert)); return PemUtil.encode(pemInfo); } /** * PKCS #7 encode a certificate. * * @return The encoding * @param cert * The certificate * @throws CryptoException * If there was a problem encoding the certificate */ public static byte[] getCertEncodedPkcs7(X509Certificate cert) throws CryptoException { return getCertsEncodedPkcs7(new X509Certificate[] { cert }); } /** * PKCS #7 encode a number of certificates. * * @return The encoding * @param certs * The certificates * @throws CryptoException * If there was a problem encoding the certificates */ public static byte[] getCertsEncodedPkcs7(X509Certificate[] certs) throws CryptoException { try { ArrayList<Certificate> encodedCerts = new ArrayList<Certificate>(); Collections.addAll(encodedCerts, certs); CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); CertPath cp = cf.generateCertPath(encodedCerts); return cp.getEncoded(PKCS7_ENCODING); } catch (CertificateException e) { throw new CryptoException(res.getString("NoPkcs7Encode.exception.message"), e); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoPkcs7Encode.exception.message"), e); } } /** * PKCS #7 encode a certificate and PEM the encoding. * * @param cert * The certificate * @return The PEM'd encoding * @throws CryptoException * If there was a problem encoding the certificate */ public static String getCertEncodedPkcs7Pem(X509Certificate cert) throws CryptoException { return getCertsEncodedPkcs7Pem(new X509Certificate[] { cert }); } /** * PKCS #7 encode a number of certificates and PEM the encoding. * * @param certs * The certificates * @return The PEM'd encoding * @throws CryptoException * If there was a problem encoding the certificates */ public static String getCertsEncodedPkcs7Pem(X509Certificate[] certs) throws CryptoException { PemInfo pemInfo = new PemInfo(PKCS7_PEM_TYPE, null, getCertsEncodedPkcs7(certs)); return PemUtil.encode(pemInfo); } /** * PKI Path encode a certificate. * * @return The encoding * @param cert * The certificate * @throws CryptoException * If there was a problem encoding the certificate */ public static byte[] getCertEncodedPkiPath(X509Certificate cert) throws CryptoException { return getCertsEncodedPkiPath(new X509Certificate[] { cert }); } /** * PKI Path encode a number of certificates. * * @return The encoding * @param certs * The certificates * @throws CryptoException * If there was a problem encoding the certificates */ public static byte[] getCertsEncodedPkiPath(X509Certificate[] certs) throws CryptoException { try { ArrayList<Certificate> encodedCerts = new ArrayList<Certificate>(); Collections.addAll(encodedCerts, certs); CertificateFactory cf = CertificateFactory.getInstance(X509_CERT_TYPE, BOUNCY_CASTLE.jce()); CertPath cp = cf.generateCertPath(encodedCerts); return cp.getEncoded(PKI_PATH_ENCODING); } catch (CertificateException e) { throw new CryptoException(res.getString("NoPkcs7Encode.exception.message"), e); } catch (NoSuchProviderException e) { throw new CryptoException(res.getString("NoPkcs7Encode.exception.message"), e); } } /** * Verify that one X.509 certificate was signed using the private key that * corresponds to the public key of a second certificate. * * @return True if the first certificate was signed by private key * corresponding to the second signature * @param signedCert * The signed certificate * @param signingCert * The signing certificate * @throws CryptoException * If there was a problem verifying the signature. */ public static boolean verifyCertificate(X509Certificate signedCert, X509Certificate signingCert) throws CryptoException { try { signedCert.verify(signingCert.getPublicKey()); return true; } // Verification failed catch (InvalidKeyException ex) { return false; } catch (SignatureException ex) { return false; } // Problem verifying catch (NoSuchProviderException ex) { throw new CryptoException(res.getString("NoVerifyCertificate.exception.message"), ex); } catch (NoSuchAlgorithmException ex) { throw new CryptoException(res.getString("NoVerifyCertificate.exception.message"), ex); } catch (CertificateException ex) { throw new CryptoException(res.getString("NoVerifyCertificate.exception.message"), ex); } } /** * Check whether or not a trust path exists between the supplied X.509 * certificate and and the supplied keystores based on the trusted * certificates contained therein, ie that a chain of trust exists between * the supplied certificate and a self-signed trusted certificate in the * KeyStores. * * @return The trust chain, or null if trust could not be established * @param cert * The certificate * @param keyStores * The KeyStores * @throws CryptoException * If there is a problem establishing trust */ public static X509Certificate[] establishTrust(X509Certificate cert, KeyStore keyStores[]) throws CryptoException { ArrayList<X509Certificate> ksCerts = new ArrayList<X509Certificate>(); for (int i = 0; i < keyStores.length; i++) { ksCerts.addAll(extractCertificates(keyStores[i])); } return establishTrust(cert, ksCerts); } private static X509Certificate[] establishTrust(X509Certificate cert, List<X509Certificate> compCerts) throws CryptoException { /* * Check whether or not a trust path exists between the supplied X.509 * certificate and and the supplied comparison certificates , ie that a * chain of trust exists between the certificate and a self-signed * trusted certificate in the comparison set */ for (int i = 0; i < compCerts.size(); i++) { X509Certificate compCert = compCerts.get(i); // Verify of certificate issuer is sam as comparison certificate's subject if (cert.getIssuerX500Principal().equals(compCert.getSubjectX500Principal())) { // Verify if the comparison certificate's private key was used to sign the certificate if (X509CertUtil.verifyCertificate(cert, compCert)) { // If the comparision certificate is self-signed then a chain of trust exists if (compCert.getSubjectX500Principal().equals(compCert.getIssuerX500Principal())) { return new X509Certificate[] { cert, compCert }; } /* * Otherwise try and establish a chain of trust from the * comparison certificate against the other comparison certificates */ X509Certificate[] tmpChain = establishTrust(compCert, compCerts); if (tmpChain != null) { X509Certificate[] trustChain = new X509Certificate[tmpChain.length + 1]; trustChain[0] = cert; System.arraycopy(tmpChain, 0, trustChain, 1, tmpChain.length); return trustChain; } } } } return null; // No chain of trust } private static List<X509Certificate> extractCertificates(KeyStore keyStore) throws CryptoException { try { List<X509Certificate> certs = new ArrayList<X509Certificate>(); for (Enumeration aliases = keyStore.aliases(); aliases.hasMoreElements();) { String alias = (String) aliases.nextElement(); if (keyStore.isCertificateEntry(alias)) { certs.add(X509CertUtil.convertCertificate(keyStore.getCertificate(alias))); } } return certs; } catch (KeyStoreException ex) { throw new CryptoException(res.getString("NoExtractCertificates.exception.message"), ex); } } /** * Check whether or not a trusted certificate in the supplied KeyStore * matches the supplied X.509 certificate. * * @param cert * The certificate * @param keyStore * The KeyStore * @return The alias of the matching certificate in the KeyStore or null if * there is no match * @throws CryptoException * If there is a problem establishing trust */ public static String matchCertificate(KeyStore keyStore, X509Certificate cert) throws CryptoException { try { for (Enumeration aliases = keyStore.aliases(); aliases.hasMoreElements();) { String alias = (String) aliases.nextElement(); if (keyStore.isCertificateEntry(alias)) { X509Certificate compCert = X509CertUtil.convertCertificate(keyStore.getCertificate(alias)); if (cert.equals(compCert)) { return alias; } } } return null; } catch (KeyStoreException ex) { throw new CryptoException(res.getString("NoMatchCertificate.exception.message"), ex); } } /** * For a given X.509 certificate get a representative alias for it in a * KeyStore. For a self-signed certificate this will be the subject's common * name (if any). For a non-self-signed certificate it will be the subject's * common name followed by the issuer's common name in brackets. Aliases * will always be in lower case. * * @param cert * The certificate * @return The alias or a blank string if none could be worked out */ public static String getCertificateAlias(X509Certificate cert) { X500Principal subject = cert.getSubjectX500Principal(); X500Principal issuer = cert.getIssuerX500Principal(); String subjectCn = extractCommonName(X500NameUtils.x500PrincipalToX500Name(subject)); String issuerCn = extractCommonName(X500NameUtils.x500PrincipalToX500Name(issuer)); if (subjectCn == null) { return ""; } if (issuerCn == null || subjectCn.equals(issuerCn)) { return subjectCn; } return MessageFormat.format("{0} ({1})", subjectCn, issuerCn); } private static String extractCommonName(X500Name name) { for (RDN rdn : name.getRDNs()) { AttributeTypeAndValue atav = rdn.getFirst(); if (atav.getType().equals(BCStyle.CN)) { return atav.getValue().toString(); } } return null; } /** * Get short name for certificate. Common name if available, otherwise use * entire distinguished name. * * @param cert * Certificate * @return Short name */ public static String getShortName(X509Certificate cert) { X500Name subject = X500NameUtils.x500PrincipalToX500Name(cert.getSubjectX500Principal()); String shortName = extractCommonName(subject); if (shortName == null) { shortName = subject.toString(); } return shortName; } /** * For a given X.509 certificate get the algorithm of its signature. Useful * as the JCE may return an unfriendly name. This method converts known * "unfriendly names" to friendly names. * * @param cert * The certificate * @return The algorithm */ public static String getCertificateSignatureAlgorithm(X509Certificate cert) { // Unfriendly JCE sig names may be actual JCE names or OIDs String algorithm = cert.getSigAlgName(); SignatureType type = SignatureType.resolveJce(algorithm); if (type != null) { algorithm = type.friendly(); } else { type = SignatureType.resolveOid(algorithm); if (type != null) { algorithm = type.friendly(); } } return algorithm; } /** * Is the supplied X.509 certificate self-signed? * * @param cert * The certificate * @return True if it is */ public static boolean isCertificateSelfSigned(X509Certificate cert) { return cert.getIssuerX500Principal().equals(cert.getSubjectX500Principal()); } }