Every method I write to encode a string in Java using 3DES can’t be decrypted back to the original string. Does anyone have a simple code snippet that can just encode and then decode the string back to the original string?
I know I’m making a very silly mistake somewhere in this code. Here’s what I’ve been working with so far:
** note, I am not returning the BASE64 text from the encrypt method, and I am not base64 un-encoding in the decrypt method because I was trying to see if I was making a mistake in the BASE64 part of the puzzle.
public class TripleDESTest { public static void main(String[] args) { String text = 'kyle boon'; byte[] codedtext = new TripleDESTest().encrypt(text); String decodedtext = new TripleDESTest().decrypt(codedtext); System.out.println(codedtext); System.out.println(decodedtext); } public byte[] encrypt(String message) { try { final MessageDigest md = MessageDigest.getInstance('md5'); final byte[] digestOfPassword = md.digest('HG58YZ3CR9'.getBytes('utf-8')); final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24); for (int j = 0, k = 16; j < 8;) { keyBytes[k++] = keyBytes[j++]; } final SecretKey key = new SecretKeySpec(keyBytes, 'DESede'); final IvParameterSpec iv = new IvParameterSpec(new byte[8]); final Cipher cipher = Cipher.getInstance('DESede/CBC/PKCS5Padding'); cipher.init(Cipher.ENCRYPT_MODE, key, iv); final byte[] plainTextBytes = message.getBytes('utf-8'); final byte[] cipherText = cipher.doFinal(plainTextBytes); final String encodedCipherText = new sun.misc.BASE64Encoder().encode(cipherText); return cipherText; } catch (java.security.InvalidAlgorithmParameterException e) { System.out.println('Invalid Algorithm'); } catch (javax.crypto.NoSuchPaddingException e) { System.out.println('No Such Padding'); } catch (java.security.NoSuchAlgorithmException e) { System.out.println('No Such Algorithm'); } catch (java.security.InvalidKeyException e) { System.out.println('Invalid Key'); } catch (BadPaddingException e) { System.out.println('Invalid Key');} catch (IllegalBlockSizeException e) { System.out.println('Invalid Key');} catch (UnsupportedEncodingException e) { System.out.println('Invalid Key');} return null; } public String decrypt(byte[] message) { try { final MessageDigest md = MessageDigest.getInstance('md5'); final byte[] digestOfPassword = md.digest('HG58YZ3CR9'.getBytes('utf-8')); final byte[] keyBytes = Arrays.copyOf(digestOfPassword, 24); for (int j = 0, k = 16; j < 8;) { keyBytes[k++] = keyBytes[j++]; } final SecretKey key = new SecretKeySpec(keyBytes, 'DESede'); final IvParameterSpec iv = new IvParameterSpec(new byte[8]); final Cipher decipher = Cipher.getInstance('DESede/CBC/PKCS5Padding'); decipher.init(Cipher.DECRYPT_MODE, key, iv); //final byte[] encData = new sun.misc.BASE64Decoder().decodeBuffer(message); final byte[] plainText = decipher.doFinal(message); return plainText.toString(); } catch (java.security.InvalidAlgorithmParameterException e) { System.out.println('Invalid Algorithm'); } catch (javax.crypto.NoSuchPaddingException e) { System.out.println('No Such Padding'); } catch (java.security.NoSuchAlgorithmException e) { System.out.println('No Such Algorithm'); } catch (java.security.InvalidKeyException e) { System.out.println('Invalid Key'); } catch (BadPaddingException e) { System.out.println('Invalid Key');} catch (IllegalBlockSizeException e) { System.out.println('Invalid Key');} catch (UnsupportedEncodingException e) { System.out.println('Invalid Key');} catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } return null; } }
Your code was fine except for the Base 64 encoding bit (which you mentioned was a test), the reason the output may not have made sense is that you were displaying a raw byte array (doing toString() on a byte array returns its internal Java reference, not the String representation of the contents). Here’s a version that’s just a teeny bit cleaned up and which prints ‘kyle boon’ as the decoded string: