If you want a consistent experience across platforms I would recommend
Chilkat. That's what we use and it makes encryption so much easier.
On Apr 4, 2013 11:58 PM, "Hiren Dabhi" <[email protected]> wrote:
> i don't know the encryption-decryption, you can try to change the last
> line for decrypt as,
>
> c.decrypt(new FileInputStream(fileNameInput)**, new FileOutputStream(**
> fileNameOutput));
>
>
> On Sunday, 18 March 2012 04:20:41 UTC+5:30, Italo Mendonça Rocha wrote:
>>
>> I'm trying to encrypt and decrypt a file using a key that the user typed. All
>> these operations are done in Android. At the moment I decrypt I get a
>> javax.crypto.**BadPaddingException: pad block corrupted. The same code works
>> normally on Windows PC. Why?
>>
>> Here is my code:
>>
>> *The call:*
>> *Encrypt:*
>> String fileNameInput = Environment.**
>> getExternalStorageDirectory().**toString() + File.separator +
>> SAVE_FOLDER + File.separator + "file";
>> String fileNameOutput = Environment.**
>> getExternalStorageDirectory().**toString() + File.separator + AVE_FOLDER
>> + File.separator + "file_crypted";
>> Crypto c = new Crypto(userKey);
>> c.encrypt(new FileInputStream(fileNameInput)**, new
>> FileOutputStream(**fileNameOutput));
>> *Decrypt:*
>> String fileNameInput = Environment.**
>> getExternalStorageDirectory().**toString() + File.separator +
>> SAVE_FOLDER + File.separator + "file_crypted";
>> String fileNameOutput = Environment.**
>> getExternalStorageDirectory().**toString() + File.separator + AVE_FOLDER
>> + File.separator + "file_decrypted";
>> Crypto c = new Crypto(userKey);
>> c.encrypt(new FileInputStream(fileNameInput)**, new
>> FileOutputStream(**fileNameOutput));
>>
>> *The class Crypto:*
>> import java.io.ByteArrayOutputStream;
>> import java.io.FileInputStream;
>> import java.io.FileOutputStream;
>> import java.io.InputStream;
>> import java.io.OutputStream;
>> import java.security.MessageDigest;
>> import java.security.SecureRandom;
>> import java.security.spec.**AlgorithmParameterSpec;
>>
>> import javax.crypto.Cipher;
>> import javax.crypto.**CipherInputStream;
>> import javax.crypto.**CipherOutputStream;
>> import javax.crypto.KeyGenerator;
>> import javax.crypto.SecretKey;
>> import javax.crypto.spec.**IvParameterSpec;
>> import javax.crypto.spec.**SecretKeySpec;
>>
>> import android.graphics.Bitmap;
>> import br.com.italomr.photocrypt.**util.Domain;
>> import br.com.italomr.photocrypt.**util.StringOutputStream;
>>
>> public class Crypto {
>> private Cipher ecipher;
>> private Cipher dcipher;
>>
>> private static final String AES = "AES";
>> private static final String AES_PADDING = "AES/CBC/PKCS5Padding";
>> private static final String MD5 = "MD5";
>> private static final String HEXES = "0123456789ABCDEF";
>>
>> /**
>> * Input a string that will be md5 hashed to create the key.
>> *
>> * @return void, cipher initialized
>> */
>>
>> public Crypto() {
>> try {
>> KeyGenerator kgen = KeyGenerator.getInstance(AES);
>> kgen.init(128);
>> this.setupCrypto(kgen.**generateKey());
>> } catch (Exception e) {
>> e.printStackTrace();
>> }
>> }
>>
>> public Crypto(String key) {
>> SecretKeySpec skey = new SecretKeySpec(getMD5(key), AES);
>> this.setupCrypto(skey);
>> }
>>
>> private void setupCrypto(SecretKey key) {
>> // Create an 8-byte initialization vector
>> byte[] iv = new byte[] { 0x00, 0x01, 0x02, 0x03, 0x04, 0x05,
>> 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f };
>>
>> AlgorithmParameterSpec paramSpec = new IvParameterSpec(iv);
>> try {
>> ecipher = Cipher.getInstance(AES_**PADDING);
>> dcipher = Cipher.getInstance(AES_**PADDING);
>>
>> // CBC requires an initialization vector
>> ecipher.init(Cipher.ENCRYPT_**MODE, key, paramSpec);
>> dcipher.init(Cipher.DECRYPT_**MODE, key, paramSpec);
>> } catch (Exception e) {
>> e.printStackTrace();
>> }
>> }
>>
>> // 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) {
>> e.printStackTrace();
>> }
>> }
>>
>> public byte[] encrypt(byte[] data) {
>> try {
>> byte[] ciphertext = ecipher.doFinal(data);
>> return ciphertext;
>> } catch (Exception e) {
>> e.printStackTrace();
>> return null;
>> }
>> }
>>
>> 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) {
>> e.printStackTrace();
>> }
>> }
>>
>> public byte[] decrypt(byte[] ciphertext) {
>> try {
>> // To convert to String
>> // String plaintext = new String(dcipher.doFinal(**
>> ciphertext),
>> // Domain.UTF8);
>> return dcipher.doFinal(ciphertext);
>> } catch (Exception e) {
>> e.printStackTrace();
>> return null;
>> }
>> }
>>
>> private static byte[] getMD5(String input) {
>> try {
>> byte[] bytesOfMessage = input.getBytes(Domain.UTF8);
>> MessageDigest md = MessageDigest.getInstance(MD5)**;
>> return md.digest(bytesOfMessage);
>> } catch (Exception e) {
>> return null;
>> }
>> }
>>
>> public static String byteToHex(byte[] raw) {
>> if (raw == null) {
>> return null;
>> }
>> final StringBuilder hex = new StringBuilder(2 * raw.length);
>> for (final byte b : raw) {
>> hex.append(HEXES.charAt((b & 0xF0) >>
>> 4)).append(HEXES.charAt((b & 0x0F)));
>> }
>> return hex.toString();
>> }
>>
>> public static byte[] hexToByte(String hexString) {
>> int len = hexString.length();
>> byte[] ba = new byte[len / 2];
>> for (int i = 0; i < len; i += 2) {
>> ba[i / 2] = (byte) ((Character.digit(hexString.**charAt(i),
>> 16) << 4) + Character.digit(hexString.**charAt(i + 1), 16));
>> }
>> return ba;
>> }
>>
>>
>> }
>>
>> Thanks in advance.
>> Ítalo Rocha
>>
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