package de.pixart.messenger.utils; import android.util.Log; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.security.InvalidKeyException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.Arrays; import javax.crypto.Cipher; import javax.crypto.CipherInputStream; import javax.crypto.CipherOutputStream; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.SecretKeySpec; import de.pixart.messenger.Config; public class EncryptDecryptFile { private static String cipher_mode = "AES/ECB/PKCS5Padding"; public static void encrypt(FileInputStream iFile, FileOutputStream oFile, String iKey) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException { byte[] key = iKey.getBytes("UTF-8"); Log.d(Config.LOGTAG, "Cipher key: " + Arrays.toString(key)); MessageDigest sha = MessageDigest.getInstance("SHA-1"); Log.d(Config.LOGTAG, "Cipher sha: " + sha.toString()); key = sha.digest(key); Log.d(Config.LOGTAG, "Cipher sha key: " + Arrays.toString(key)); key = Arrays.copyOf(key, 16); // use only first 128 bit Log.d(Config.LOGTAG, "Cipher sha key 16 bytes: " + Arrays.toString(key)); SecretKeySpec sks = new SecretKeySpec(key, "AES"); Cipher cipher = Cipher.getInstance(cipher_mode); cipher.init(Cipher.ENCRYPT_MODE, sks); Log.d(Config.LOGTAG, "Cipher IV: " + Arrays.toString(cipher.getIV())); CipherOutputStream cos = new CipherOutputStream(oFile, cipher); Log.d(Config.LOGTAG, "Encryption with: " + cos.toString()); int b; byte[] d = new byte[8]; while ((b = iFile.read(d)) != -1) { cos.write(d, 0, b); } cos.flush(); cos.close(); iFile.close(); } public static void decrypt(FileInputStream iFile, FileOutputStream oFile, String iKey) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException { byte[] key = iKey.getBytes("UTF-8"); Log.d(Config.LOGTAG, "Cipher key: " + Arrays.toString(key)); MessageDigest sha = MessageDigest.getInstance("SHA-1"); Log.d(Config.LOGTAG, "Cipher sha: " + sha.toString()); key = sha.digest(key); Log.d(Config.LOGTAG, "Cipher sha key: " + Arrays.toString(key)); key = Arrays.copyOf(key, 16); // use only first 128 bit Log.d(Config.LOGTAG, "Cipher sha key 16 bytes: " + Arrays.toString(key)); SecretKeySpec sks = new SecretKeySpec(key, "AES"); Cipher cipher = Cipher.getInstance(cipher_mode); cipher.init(Cipher.DECRYPT_MODE, sks); Log.d(Config.LOGTAG, "Cipher IV: " + Arrays.toString(cipher.getIV())); CipherInputStream cis = new CipherInputStream(iFile, cipher); Log.d(Config.LOGTAG, "Decryption with: " + cis.toString()); int b; byte[] d = new byte[8]; while ((b = cis.read(d)) != -1) { oFile.write(d, 0, b); } oFile.flush(); oFile.close(); cis.close(); } }