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| /*
* RSAEncryptor.java
*
* Created on 17 juin 2006, 15:58
*
* To change this template, choose Tools | Template Manager
* and open the template in the editor.
*/
package Security;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.security.GeneralSecurityException;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
/**
*
* @author Absil Romain
*/
public class RSAEncryptor
{
/**
* Generate a pair of key, write the public in publicOutputFileName and the
* private in privateOutputFileName.
* @param publicOutputFileName the file where the public key is written in.
* @param privateOutputFileName the file where the private key is written in.
**/
public static void generateKeys(String publicInputFileName,
String privateOutputFileName)
{
try
{
KeyPairGenerator pairgen = KeyPairGenerator.getInstance("RSA");
SecureRandom random = new SecureRandom();
pairgen.initialize(2048, random);
KeyPair keyPair = pairgen.generateKeyPair();
ObjectOutputStream out = new ObjectOutputStream(
new FileOutputStream(publicInputFileName));
out.writeObject(keyPair.getPublic());
out.close();
out = new ObjectOutputStream(
new FileOutputStream(privateOutputFileName));
out.writeObject(keyPair.getPrivate());
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}
/**
* Encrytps the file inputFileName and saves the result in the file
* outputFileName, with the specified key keyFileName.
* @param inputFileNane the file to encrypt.
* @param outputFileName the file to save the encrypting result in.
* @param keyFileName the key to use to encrypt the file.
**/
public static void encryptFile(String inputFileName, String outputFileName,
String keyFileName)
{
try
{
KeyGenerator keygen = KeyGenerator.getInstance("AES");
SecureRandom random = new SecureRandom();
keygen.init(random);
SecretKey key = keygen.generateKey();
//emballe avec la clé publique RSA
ObjectInputStream keyIn = new ObjectInputStream(
new FileInputStream(keyFileName));
Key publicKey = (Key)keyIn.readObject();
keyIn.close();
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.WRAP_MODE, publicKey);
byte[] wrappedKey = cipher.wrap(key);
DataOutputStream out = new DataOutputStream(
new FileOutputStream(outputFileName));
out.writeInt(wrappedKey.length);
out.write(wrappedKey);
InputStream in = new FileInputStream(inputFileName);
cipher = cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, key);
crypt(in, out, cipher);
in.close();
out.close();
}
catch (Exception e)
{
e.printStackTrace();
}
}
/**
* Decrytps the file inputFileName and saves the result in the file
* outputFileName, with the specified key keyFileName.
* @param inputFileName the file to decrypt.
* @param outputFileName the file to save the decrypting result in.
* @param keyFileName the key to use to decrypt the file.
**/
public static void decryptFile(String inputFileName, String outputFileName,
String keyFileName)
{
try
{
DataInputStream in = new DataInputStream(
new FileInputStream(inputFileName));
int length = in.readInt();
byte[] wrappedKey = new byte[length];
in.read(wrappedKey, 0, length);
//déballe avec la clé RSA
ObjectInputStream keyIn = new ObjectInputStream(
new FileInputStream(keyFileName));
Key privateKey = (Key)keyIn.readObject();
keyIn.close();
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.UNWRAP_MODE, privateKey);
Key key = cipher.unwrap(wrappedKey, "AES", Cipher.SECRET_KEY);
OutputStream out = new FileOutputStream(outputFileName);
cipher = cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, key);
crypt(in, out, cipher);
in.close();
out.close();
}
catch (Exception ex)
{
ex.printStackTrace();
}
}
private static void crypt(InputStream in, OutputStream out, Cipher cipher)
throws IOException, GeneralSecurityException
{
int blockSize = cipher.getBlockSize();
int outputSize = cipher.getOutputSize(blockSize);
byte[] inBytes = new byte[blockSize];
byte[] outBytes = new byte[outputSize];
int inLength = 0;
boolean done = false;
while(!done)
{
inLength = in.read(inBytes);
if(inLength == blockSize)
{
int outLength = cipher.update(inBytes, 0, blockSize, outBytes);
out.write(outBytes, 0, outLength);
}
else
done = true;
}
if(inLength > 0)
outBytes = cipher.doFinal(inBytes, 0, inLength);
else
outBytes = cipher.doFinal();
out.write(outBytes);
}
} |
Cryptage/Decryptage de String
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