http://www.guj.com.br/posts/list/5.java JForum - http://www.jforum.net Esta é a classe que tem os metodos de encriptação e desencriptação que eu apanhei no google em java almanac em [url]http://www.exampledepot.com/egs/javax.crypto/DesFile.html[/url]
[code]
public class DesEncrypter {
Cipher ecipher;
Cipher dcipher;

DesEncrypter(SecretKey key) {
// Create an 8-byte initialization vector
byte[] iv = new byte[]{
(byte)0x8E, 0x12, 0x39, (byte)0x9C,
0x07, 0x72, 0x6F, 0x5A
};
AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
try {
ecipher = Cipher.getInstance("DES/CBC/PKCS5Padding");
dcipher = Cipher.getInstance("DES/CBC/PKCS5Padding");

// CBC requires an initialization vector
ecipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
dcipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
} catch (java.security.InvalidAlgorithmParameterException e) {
} catch (javax.crypto.NoSuchPaddingException e) {
} catch (java.security.NoSuchAlgorithmException e) {
} catch (java.security.InvalidKeyException e) {
}
}

// Buffer used to transport the bytes from one stream to another
byte[] buf = new byte[1024];

public void encrypt(InputStream in, OutputStream out) {
try {
// Bytes written to out will be encrypted
out = new CipherOutputStream(out, ecipher);

// Read in the cleartext bytes and write to out to encrypt
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
out.close();
} catch (java.io.IOException e) {
}
}

public void decrypt(InputStream in, OutputStream out) {
try {
// Bytes read from in will be decrypted
in = new CipherInputStream(in, dcipher);

// Read in the decrypted bytes and write the cleartext to out
int numRead = 0;
while ((numRead = in.read(buf)) >= 0) {
out.write(buf, 0, numRead);
}
out.close();
} catch (java.io.IOException e) {
}
}
}
[/code]


eu criei uma classe que tem um metodo que chama a class acima e usa o metodo encript da seguinte forma :
[code]
try {

key = KeyGenerator.getInstance("DES").generateKey();

System.out.println(key);

// Create encrypter/decrypter class
DesEncrypter encrypter = new DesEncrypter(key);

// Encrypt
String nfile = new String (lemails.getSelectedValue().toString().trim());
encrypter.encrypt(new FileInputStream("processados/"+nfile),
new FileOutputStream("processados/"+ nfile+"_"+key));

// Decrypt
/*
encrypter.decrypt(new FileInputStream("ciphertext"),
new FileOutputStream("cleartext2"));
*/

} catch (Exception e) {
e.printStackTrace();
}
[/code]

tudo funciona beleza .

O problema está em desencriptar este ficheiro encriptado. Quando tento usar o metodo decrypt ele criar um novo ficheiro mas ainda encriptado .
[code]
~try {


SecretKey key = KeyGenerator.getInstance("DES").generateKey();


System.out.println(key);

DesEncrypter encrypter = new DesEncrypter(key);

String nfile = new String (lemails.getSelectedValue().toString().trim());

// Decrypt

encrypter.decrypt(new FileInputStream("processados/"+nfile),
new FileOutputStream("processados/cleartext2.txt"));

}catch(Exception ex){
ex.printStackTrace();

}
[/code]

minha duvida é :

Como faço para poder desencriptar este ficheiro ]]> http://www.guj.com.br/prepost/195412/981197/encriptar-ficheiro http://www.guj.com.br/prepost/195412/981197/encriptar-ficheiro GMT