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2010-06-01T05:01:40Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== An example of using RSA to encrypt a single asymmetric key. ==



<source lang="java">
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class MainClass {
public static void main(String[] args) throws Exception {
KeyGenerator keyGenerator = KeyGenerator.getInstance("Blowfish");
keyGenerator.init(128);
Key blowfishKey = keyGenerator.generateKey();
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair = keyPairGenerator.genKeyPair();
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());
byte[] blowfishKeyBytes = blowfishKey.getEncoded();
System.out.println(new String(blowfishKeyBytes));
byte[] cipherText = cipher.doFinal(blowfishKeyBytes);
System.out.println(new String(cipherText));
cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
byte[] decryptedKeyBytes = cipher.doFinal(cipherText);
System.out.println(new String(decryptedKeyBytes));
SecretKey newBlowfishKey = new SecretKeySpec(decryptedKeyBytes, "Blowfish");
}
}</source>



== An RSA sample application ==



<source lang="java">
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.spec.RSAKeyGenParameterSpec;
import java.security.spec.RSAPublicKeySpec;
public class MainClass {
public static void main(String[] args) throws Exception {
int eValue = 79;
int bitLength = 1024; // KeySize
BigInteger e = e = new BigInteger(Integer.toString(eValue));
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(bitLength);
KeyPair kp = kpg.generateKeyPair();
KeyFactory kfactory = KeyFactory.getInstance("RSA");
RSAPublicKeySpec kspec = (RSAPublicKeySpec) kfactory.getKeySpec(kp.getPublic(),
RSAPublicKeySpec.class);
kpg = KeyPairGenerator.getInstance("RSA", "SunRsaSign");
e = new BigInteger(Integer.toString(eValue));
System.out.println("e =" + e);
RSAKeyGenParameterSpec param = new RSAKeyGenParameterSpec(bitLength, e);
kpg.initialize(param);
kp = kpg.generateKeyPair();
kfactory = KeyFactory.getInstance("RSA", "SunRsaSign");
kspec = (RSAPublicKeySpec) kfactory.getKeySpec(kp.getPublic(),RSAPublicKeySpec.class);
}
}</source>



== Basic RSA example. ==



<source lang="java">
import java.math.BigInteger;
import java.security.KeyFactory;
import java.security.Security;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;
public class MainClass {
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
byte[] input = new byte[] { (byte) 0xbe, (byte) 0xef };
Cipher cipher = Cipher.getInstance("RSA/None/NoPadding", "BC");
KeyFactory keyFactory = KeyFactory.getInstance("RSA", "BC");
RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(
"12345678", 16), new BigInteger("11", 16));
RSAPrivateKeySpec privKeySpec = new RSAPrivateKeySpec(new BigInteger(
"12345678", 16), new BigInteger("12345678",
16));
RSAPublicKey pubKey = (RSAPublicKey) keyFactory.generatePublic(pubKeySpec);
RSAPrivateKey privKey = (RSAPrivateKey) keyFactory.generatePrivate(privKeySpec);
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] cipherText = cipher.doFinal(input);
System.out.println("cipher: " + new String(cipherText));
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] plainText = cipher.doFinal(cipherText);
System.out.println("plain : " + new String(plainText));
}
}</source>



== Creates a it RSA key pair and stores it to the filesystem as two files ==



<source lang="java">
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;
public class MainClass {
public static void main(String[] args) throws Exception {
String password = "password";
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair = keyPairGenerator.genKeyPair();
String publicKeyFilename = "public";
byte[] publicKeyBytes = keyPair.getPublic().getEncoded();
FileOutputStream fos = new FileOutputStream(publicKeyFilename);
fos.write(publicKeyBytes);
fos.close();
String privateKeyFilename = "privateKeyFilename";
byte[] privateKeyBytes = keyPair.getPrivate().getEncoded();
byte[] encryptedPrivateKeyBytes = passwordEncrypt(password.toCharArray(), privateKeyBytes);
fos = new FileOutputStream(privateKeyFilename);
fos.write(encryptedPrivateKeyBytes);
fos.close();
}
private static byte[] passwordEncrypt(char[] password, byte[] plaintext) throws Exception {
int MD5_ITERATIONS = 1000;
byte[] salt = new byte[8];
SecureRandom random = new SecureRandom();
random.nextBytes(salt);
PBEKeySpec keySpec = new PBEKeySpec(password);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");
SecretKey key = keyFactory.generateSecret(keySpec);
PBEParameterSpec paramSpec = new PBEParameterSpec(salt, MD5_ITERATIONS);
Cipher cipher = Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
cipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
byte[] ciphertext = cipher.doFinal(plaintext);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
baos.write(salt);
baos.write(ciphertext);
return baos.toByteArray();
}
}</source>



== RSA example with OAEP Padding and random key generation. ==



<source lang="java">
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
public class MainClass {
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
byte[] input = "abc".getBytes();
Cipher cipher = Cipher.getInstance("RSA/None/OAEPWithSHA1AndMGF1Padding", "BC");
SecureRandom random = new SecureRandom();
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "BC");
generator.initialize(386, random);
KeyPair pair = generator.generateKeyPair();
Key pubKey = pair.getPublic();
Key privKey = pair.getPrivate();
cipher.init(Cipher.ENCRYPT_MODE, pubKey, random);
byte[] cipherText = cipher.doFinal(input);
System.out.println("cipher: " + new String(cipherText));
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] plainText = cipher.doFinal(cipherText);
System.out.println("plain : " + new String(plainText));
}
}</source>



== RSA example with PKCS #1 Padding. ==



<source lang="java">
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
public class MainClass {
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
byte[] input = "abc".getBytes();
Cipher cipher = Cipher.getInstance("RSA/None/PKCS1Padding", "BC");
SecureRandom random = new SecureRandom();
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "BC");
generator.initialize(256, random);
KeyPair pair = generator.generateKeyPair();
Key pubKey = pair.getPublic();
Key privKey = pair.getPrivate();
cipher.init(Cipher.ENCRYPT_MODE, pubKey, random);
byte[] cipherText = cipher.doFinal(input);
System.out.println("cipher: " + new String(cipherText));
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] plainText = cipher.doFinal(cipherText);
System.out.println("plain : " + new String(plainText));
}
}</source>



== RSA example with random key generation. ==



<source lang="java">
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import javax.crypto.Cipher;
public class MainClass {
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
byte[] input = "aa".getBytes();
Cipher cipher = Cipher.getInstance("RSA/None/NoPadding", "BC");
SecureRandom random = new SecureRandom();
KeyPairGenerator generator = KeyPairGenerator.getInstance("RSA", "BC");
generator.initialize(256, random);
KeyPair pair = generator.generateKeyPair();
Key pubKey = pair.getPublic();
Key privKey = pair.getPrivate();
cipher.init(Cipher.ENCRYPT_MODE, pubKey, random);
byte[] cipherText = cipher.doFinal(input);
System.out.println("cipher: " + new String(cipherText));
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] plainText = cipher.doFinal(cipherText);
System.out.println("plain : " + new String(plainText));
}
}</source>



== RSA Signature Generation ==



<source lang="java">
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;
import java.security.Security;
import java.security.Signature;
public class MainClass {
public static void main(String[] args) throws Exception {
Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA", "BC");
keyGen.initialize(512, new SecureRandom());
KeyPair keyPair = keyGen.generateKeyPair();
Signature signature = Signature.getInstance("SHA1withRSA", "BC");
signature.initSign(keyPair.getPrivate(), new SecureRandom());
byte[] message = "abc".getBytes();
signature.update(message);
byte[] sigBytes = signature.sign();
signature.initVerify(keyPair.getPublic());
signature.update(message);
System.out.println(signature.verify(sigBytes));
}
}</source>



== Simple Digital Signature Example ==



<source lang="java">
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.Signature;
import sun.misc.BASE64Encoder;
public class MainClass {
public static void main(String[] args) throws Exception {
KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
kpg.initialize(1024);
KeyPair keyPair = kpg.genKeyPair();
byte[] data = "test".getBytes("UTF8");
Signature sig = Signature.getInstance("MD5WithRSA");
sig.initSign(keyPair.getPrivate());
sig.update(data);
byte[] signatureBytes = sig.sign();
System.out.println("Singature:" + new BASE64Encoder().encode(signatureBytes));
sig.initVerify(keyPair.getPublic());
sig.update(data);
System.out.println(sig.verify(signatureBytes));
}
}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010