Java Digital certificate

Before building the Java code implementation, we need to complete the production of the certificate.
1. Generate the Keystroe file
Execute the following command at the command line:

Keytool-genkey-validity 36000-alias jlxrsa-keyalg rsa-keystore d:\jlxrsz.keystore

which
-genkey indicates that the key is generated
-validity Specify the certificate validity period, this is 36000 days
-alias Specifies the alias, this is www.zlex.org
-keyalg Specifies the algorithm, here is the RSA
-keystore Specify the storage location, this is d:\zlex.keystore

Here I use the password for 123456

2. Generate a self-signed certificate
Light has KeyStore file is not enough, also need certificate file, certificate is directly provided to the outside public key credentials.
To export a certificate:

Keytool-export-keystore D:\jlxrsa.keystore-alias Jlxrsa-file D:\JLXRSA.CER-RFC

which
-export specified as an export operation
-keystore specifying keystore files
-alias specifying an alias in the export KeyStore file
-file pointing to the export path
-rfc output in text format, i.e. output in BASE64 encoding
The code here is 123456 .

Ok, get ready to finish, start Java implementation!

Package Cert;import Java.security.MessageDigest;  Import Javax.crypto.KeyGenerator;  Import Javax.crypto.Mac;    Import Javax.crypto.SecretKey;  Import Javax.crypto.spec.secretkeyspec;import Sun.misc.BASE64Decoder;    Import Sun.misc.BASE64Encoder; /** * Basic Cryptographic components * * @author * @version 1.0 * @since 1.0 * * Public abstract class Coder {public static final STR      ing Key_sha = "SHA";        public static final String key_md5 = "MD5";       /** * Mac algorithm can choose the following algorithms * * <pre> * HmacMD5 * HmacSHA1 * HmacSHA256 * HmacSHA384        * HMACSHA512 * </pre> * * public static final String Key_mac = "HmacMD5"; /** * BASE64 Decryption * * @param key * @return * @throws Exception */public static byte[] de      CryptBASE64 (String key) throws Exception {return (new Base64decoder ()). Decodebuffer (key); }/** * BASE64 encryption * * @param key * @return * @throws exception */public static String encryptBASE64 (byte[] key) throws Exception {return (new Base64encoder ()). Enc      Odebuffer (key); }/** * MD5 encryption * * @param data * @return * @throws Exception */public static by          Te[] EncryptMD5 (byte[] data) throws Exception {messagedigest MD5 = messagedigest.getinstance (KEY_MD5);            Md5.update (data);        return Md5.digest (); }/** * SHA encryption * * @param data * @return * @throws Exception */public static by          Te[] Encryptsha (byte[] data) throws Exception {MessageDigest sha = messagedigest.getinstance (Key_sha);            Sha.update (data);        return Sha.digest (); }/** * Initialize HMAC key * * @return * @throws Exception */public static String Initmackey            () throws Exception {Keygenerator keygenerator = keygenerator.getinstance (KEY_MAC); Secretkey secretkey = KeYgenerator.generatekey ();      Return encryptBASE64 (secretkey.getencoded ());      }/** * HMAC encryption * * @param data * @param key * @return * @throws Exception */ public static byte[] Encrypthmac (byte[] data, String key) throws Exception {Secretkey Secretkey = new Secre          Tkeyspec (decryptBASE64 (key), KEY_MAC);          Mac Mac = Mac.getinstance (Secretkey.getalgorithm ());            Mac.init (Secretkey);        return mac.dofinal (data);   }  }

Package Cert;import Java.io.fileinputstream;import Java.security.keystore;import java.security.privatekey;import Java.security.publickey;import Java.security.signature;import Java.security.cert.certificate;import Java.security.cert.certificatefactory;import Java.security.cert.x509certificate;import Java.util.Date;import javax.crypto.cipher;/** * Certificate Component * * @author * @version 1.0 * @since 1.0 */public abstract class Certificatecoder extends Coder {/** * java KeyStore (Java key store,jks) Key_store */public static final String Key_store = "JKS";p ublic static final Strin G X509 = "n";/** * obtains private key from KeyStore * * @param keystorepath * @param alias * @param password * @return * @throws Excepti On */private static Privatekey Getprivatekey (String keystorepath, string alias,string password) throws Exception {Keystor E ks = getkeystore (keystorepath, password); Privatekey key = (Privatekey) ks.getkey (alias, Password.tochararray ()); return key;} /** * obtained public key by certificate * * @param certificatepath * @return * @tHrows Exception */private static PublicKey Getpublickey (String certificatepath) throws Exception {Certificate Certificate = getcertificate (Certificatepath); PublicKey key = Certificate.getpublickey (); return key;} /** * Get Certificate * * @param certificatepath * @return * @throws Exception */private static Certificate getcertificate ( String Certificatepath) throws Exception {certificatefactory certificatefactory = certificatefactory.getinstance (X509 ); FileInputStream in = new FileInputStream (Certificatepath); Certificate Certificate = Certificatefactory.generatecertificate (in); In.close (); return Certificate;} /** * Get certificate * * @param keystorepath * @param alias * @param password * @return * @throws Exception */private Stat IC Certificate getcertificate (String keystorepath,string Alias, string password) throws Exception {KeyStore KS = Getkeysto Re (keystorepath, password); Certificate Certificate = ks.getcertificate (alias); return Certificate;} /** * Get keystore * * @param keystorepath * @param Password * @return * @throws Exception */private static KeyStore Getkeystore (string keystorepath, string password) throws Exception {FileInputStream is = new FileInputStream (Keystorepath); KeyStore ks = keystore.getinstance (Key_store); Ks.load (is, Password.tochararray ()); Is.close (); return KS;} /** * Private Key Encryption * * @param data * @param keystorepath * @param alias * @param password * @return * @throws Exception */public Static byte[] Encryptbyprivatekey (byte[] data, string keystorepath,string Alias, string password) throws Exception {//Get private Key Privatekey Privatekey = Getprivatekey (Keystorepath, alias, password);//Data encryption cipher cipher = Cipher.getinstance ( Privatekey.getalgorithm ()); Cipher.init (Cipher.encrypt_mode, Privatekey); return cipher.dofinal (data);} /** * Private Key decryption * * @param data * @param keystorepath * @param alias * @param password * @return * @throws Exception */public Static byte[] Decryptbyprivatekey (byte[] data, string keystorepath,string Alias, string password) throws Exception {//Get private Key PrivaTekey Privatekey = Getprivatekey (Keystorepath, alias, password);//Data encryption cipher cipher = Cipher.getinstance ( Privatekey.getalgorithm ()); Cipher.init (Cipher.decrypt_mode, Privatekey); return cipher.dofinal (data);} /** * Public Key Encryption * * @param data * @param certificatepath * @return * @throws Exception */public static byte[] Encryptbypublick EY (byte[] data, String Certificatepath) throws Exception {//Get public key PublicKey PublicKey = Getpublickey (Certificatepath);// Data encryption Cipher cipher = Cipher.getinstance (Publickey.getalgorithm ()); Cipher.init (Cipher.encrypt_mode, PublicKey); return cipher.dofinal (data);} /** * Public Key decryption * * @param data * @param certificatepath * @return * @throws Exception */public static byte[] Decryptbypublick EY (byte[] data, String Certificatepath) throws Exception {//Get public key PublicKey PublicKey = Getpublickey (Certificatepath);// Data encryption Cipher cipher = Cipher.getinstance (Publickey.getalgorithm ()); Cipher.init (Cipher.decrypt_mode, PublicKey); return cipher.dofinal (data);} /** * Verify Certificate * * @paramCertificatepath * @return */public static Boolean verifycertificate (String certificatepath) {return verifycertificate ( New Date (), Certificatepath);} /** * Verify that the certificate is expired or invalid * * @param date * @param certificatepath * @return */public static Boolean verifycertificate (D Ate date, String Certificatepath) {Boolean status = true;try {//Get certificate Certificate Certificate = getcertificate (certificatep ATH);//Verify that the certificate is expired or invalid status = Verifycertificate (date, certificate);} catch (Exception e) {status = FALSE;} return status;} /** * Verify that the certificate is expired or invalid * * @param date * @param certificate * @return */private static Boolean verifycertificate (date date, Ce Rtificate certificate) {Boolean status = true;try {x509certificate x509certificate = (x509certificate) certificate; X509certificate.checkvalidity (date);} catch (Exception e) {status = FALSE;} return status;}  /** * Signature * * @param keystorepath * @param alias * @param password * * @return * @throws Exception */public static String Sign (byte[) sign, String Keystorepath,String alias,string password) throws Exception {//Get certificate X509Certificate x509certificate = (x509certificate) GetCertificate (Keystorepath, alias, password);//Get private key KeyStore KS = Getkeystore (keystorepath, password);// Get the private key privatekey Privatekey = (privatekey) Ks.getkey (Alias,password.tochararray ());//build signature Signature Signature = Signature.getinstance (X509certificate.getsigalgname ()); Signature.initsign (Privatekey); signature.update (sign); Return encryptBASE64 (Signature.sign ());} /** * Verify Signature * * @param data * @param sign * @param certificatepath * @return * @throws Exception */public Static Boolean V Erify (byte[] data, String sign,string Certificatepath) throws Exception {//Get certificate X509Certificate x509certificate = (x509ce rtificate) getcertificate (Certificatepath);//Get public key PublicKey PublicKey = X509certificate.getpublickey ();// Build Signature Signature Signature = Signature.getinstance (X509certificate.getsigalgname ()); signature.initverify (PublicKey); Signature.update (data); return signature.verify (decryptBASE64 (sign));} /** * Verify Certificate * * @param keystorepath * @param alias * @param password * @return */public static Boolean Verifycert Ificate (date date, string keystorepath,string Alias, string password) {Boolean status = true;try {Certificate Certificate = GetCertificate (Keystorepath, alias,password); status = Verifycertificate (date, certificate);} catch (Exception e) {status = FALSE;} return status;} /** * Verify Certificate * * @param keystorepath * @param alias * @param password * @return */public static Boolean Verifycert Ificate (String keystorepath, string alias,string password) {return verifycertificate (new Date (), Keystorepath, alias, password);}}

Package Cert;import static Org.junit.assert.*;import org.junit.Test; /** * * @author * @version 1.0 * @since 1.0 */public class Certificatecodertest {private String password = "      123456 ";      Private String alias = "Jlxrsa";      Private String Certificatepath = "D:/jlx.cer";        Private String Keystorepath = "D:/jlx.keystore";          @Test public void Test () throws Exception {System.err.println ("Key cryptography-private key decryption");          String inputstr = "Ceritifcate";            byte[] data = Inputstr.getbytes ();            Byte[] Encrypt = certificatecoder.encryptbypublickey (data, Certificatepath);          Byte[] Decrypt = Certificatecoder.decryptbyprivatekey (encrypt, Keystorepath, alias, password);            String outputstr = new string (decrypt);            System.err.println ("Before encryption:" + Inputstr + "\n\r" + "after decryption:" + outputstr);            Verify data consistency assertarrayequals (data, decrypt); Verify that the certificate is valid Asserttrue (certifIcatecoder.verifycertificate (Certificatepath));            } @Test public void Testsign () throws Exception {System.err.println ("private key encryption-key decryption");          String inputstr = "sign";            byte[] data = Inputstr.getbytes ();            byte[] Encodeddata = Certificatecoder.encryptbyprivatekey (data, Keystorepath, alias, password);            byte[] Decodeddata = Certificatecoder.decryptbypublickey (Encodeddata, Certificatepath);          String outputstr = new string (decodeddata);          System.err.println ("Before encryption:" + Inputstr + "\n\r" + "after decryption:" + outputstr);            Assertequals (Inputstr, OUTPUTSTR);          SYSTEM.ERR.PRINTLN ("Private key signature--public key verification signature");          Generate signature String sign = certificatecoder.sign (Encodeddata, Keystorepath, alias, password);            System.err.println ("signature: \ r" + sign);  Verify that the signature is Boolean status = Certificatecoder.verify (Encodeddata, sign, certificatepath);        System.err.println ("Status: \ r" + status);        Asserttrue (status);   }  }

　　

Java Digital certificate