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PODecrypt password with salt using 3DES
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2011-10-26T09:06:17.030
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I have a class named DESHelper that used to encrypt and decrypt password with a salt. Salt is username of that user. But this class still fail when it decrypt. My class: <pre><code>public class DESHelper { private String keyPass = "KeyPass"; private String keyAlias = "keyAlias"; private String keyStorePass="keyStorePass"; private KeyStore ks = null; private static final String KEYSTORE_PATH = "keystore/mykeystore.keystore"; private static final String KEYSTORE_TYPE = "jceks"; protected static String DES_KEY = "pin"; private Map<String, byte[]> mKeys = new HashMap<String, byte[]>(); public String decrypt(byte[] message, String salt) throws Exception { SecretKey secretKey = getSecretKey(); if (secretKey == null) { throw new GeneralSecurityException("No secret key"); } final IvParameterSpec iv = new IvParameterSpec(generateIV(keyAlias, salt, DES_KEY)); final Cipher decipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); decipher.init(Cipher.DECRYPT_MODE, secretKey, iv); final byte[] plainText = decipher.doFinal(message); return new String(plainText, "UTF-8"); } public String encrypt(String value, String salt) { byte ciphertext[][] = new byte[2][]; try { SecretKey secretKey = getSecretKey(); if (secretKey == null) { throw new GeneralSecurityException("No secret key"); } Cipher cipher = Cipher.getInstance("DESede/CBC/PKCS5Padding"); byte iv[] = generateIV(keyAlias, salt, DES_KEY); cipher.init(Cipher.ENCRYPT_MODE, secretKey, new IvParameterSpec(iv)); ciphertext[0] = cipher.update(stringToByteArray(value)); ciphertext[1] = cipher.doFinal(generateMAC(keyAlias, salt, DES_KEY, value)); } catch (GeneralSecurityException gse) { gse.printStackTrace(); return null; } if (ciphertext[0] == null) { ciphertext[0] = new byte[0]; } if (ciphertext[1] == null) { ciphertext[1] = new byte[0]; } byte ct[] = new byte[ciphertext[0].length + ciphertext[1].length]; System.arraycopy(ciphertext[0], 0, ct, 0, ciphertext[0].length); System.arraycopy(ciphertext[1], 0, ct, ciphertext[0].length, ciphertext[1].length); // Convert encrypted bytes to a String StringBuffer result = new StringBuffer(2 * ct.length + 1); result.append("b"); // first byte indicates encoding method. Base64 enc = new Base64(); result.append(enc.encode(ct)); return result.toString(); } /** * * @return * @throws InvalidKeyException * @throws NoSuchAlgorithmException * @throws GeneralSecurityException */ public SecretKey getSecretKey() throws InvalidKeyException, NoSuchAlgorithmException, GeneralSecurityException{ byte des_key[]; SecretKeyFactory secretKeyFactory = SecretKeyFactory.getInstance("DESede") ; if (secretKeyFactory == null) { throw new GeneralSecurityException("No DESede factory"); } try { des_key = getKey(keyAlias); } catch (IOException e) { e.printStackTrace(); return null; } SecretKey secretKey = secretKeyFactory.generateSecret(new DESedeKeySpec(des_key)); return secretKey; } /** * Generate MAC */ protected byte[] generateMAC(String type,String salt,String key,String value) { try { MessageDigest md = MessageDigest.getInstance("SHA-1"); if (type!=null) { md.update(stringToByteArray(type)); } if (salt!=null) { md.update(stringToByteArray(salt)); } if (key!=null) { md.update(stringToByteArray(key)); } if (value!=null) { md.update(stringToByteArray(value)); } byte[] sha = md.digest(); byte[] mac = new byte[4]; for (int scan=0;scan<sha.length;scan++) { mac[scan%4]=(byte)(mac[scan%4]^sha[scan]); } return mac; } catch (NoSuchAlgorithmException ex) { throw new IllegalStateException(ex.getMessage()); } } protected byte[] generateIV(String type,String salt,String key) { try { MessageDigest md = MessageDigest.getInstance("SHA-1"); if (type!=null) { md.update(stringToByteArray(type)); } if (salt!=null) { md.update(stringToByteArray(salt)); } if (key!=null) { md.update(stringToByteArray(key)); } byte[] sha = md.digest(); byte[] iv = new byte[8]; for (int scan=0;scan<sha.length;scan++) { iv[scan%8]=(byte)(iv[scan%8]^sha[scan]); } return iv; } catch (NoSuchAlgorithmException ex) { throw new IllegalStateException(ex.getMessage()); } } protected byte[] getKey(String alias) throws GeneralSecurityException, IOException { synchronized (mKeys) { byte k[] = mKeys.get(alias); if (k != null) { return k; } } byte key[] = getKeystoreKey(alias, 192); if (key == null) { return null; } if (key.length != 24) { return null; } synchronized (mKeys) { mKeys.put(alias, key); return key; } } protected byte[] stringToByteArray(String aString) { try { return aString.getBytes("UTF-8"); } catch (java.io.UnsupportedEncodingException ex) { System.out.println("Exception in stringToByteArray " + ex.getMessage()); return null; } } /** * Returns String From An Array Of Bytes */ private String bytes2String(byte[] bytes) { StringBuffer stringBuffer = new StringBuffer(); for (int i = 0; i <= bytes.length; i++) { stringBuffer.append((char) bytes[i]); } return stringBuffer.toString(); } protected byte[] getKeystoreKey(String aKeyName,int size) throws GeneralSecurityException, IOException { Key key = getKeystore().getKey(aKeyName, keyPass.toCharArray()); if (key==null) { System.out.println("KeyStore key "+aKeyName+" not found"); return null; } byte keyBytes[] = key.getEncoded(); if (keyBytes.length != (size/8) ) { System.out.println("KeyStore key "+aKeyName+" invalid length. Expected:"+size+" was: "+(keyBytes.length*8)); return null; } return keyBytes; } protected KeyStore getKeystore() throws GeneralSecurityException, IOException { if ( ks == null ) { ks = KeyStore.getInstance(KEYSTORE_TYPE); char[] password = keyStorePass.toCharArray(); if (password == null) { System.out.println("Couldn't get keystore password from config"); } // get the keystore as a resource InputStream is = getClass().getClassLoader().getResourceAsStream(KEYSTORE_PATH); try { ks.load(is, password); } finally { if (is != null) { is.close(); } } } return ks; } public class Base64 { private char sBase64[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray(); /** Creates a new instance of Base64 */ public Base64() { } public byte[] decode(String aSource) { int aSource_length=aSource.length(); while (aSource_length>0 && aSource.charAt(aSource_length-1)=='=') aSource_length--; if (aSource_length%4==1) { return null; } int len = (aSource_length/4)*3 + aSource_length%4 - (aSource_length%4==0?0:1); byte result[] = new byte[len]; int o_ofs=0; int i_ofs=0; while (i_ofs<aSource_length) { int i24=0; for (int bscan=0;bscan<4;bscan++) { if (i_ofs<aSource_length) { int decode = decode(aSource.charAt(i_ofs)); if (decode==-1) return null; i24=(i24<<6)+decode; } else { i24=i24<<6; } i_ofs++; } if (o_ofs<len) { result[o_ofs++]=(byte)(i24>>16); } if (o_ofs<len) { result[o_ofs++]=(byte)(i24>>8); } if (o_ofs<len) { result[o_ofs++]=(byte)(i24); } } return result; } private int decode(char c) { if (c>='A' && c<='Z') { return c-'A'; } if (c>='a' && c<='z') { return c-'a'+26; } if (c>='0' && c<='9') { return c-'0'+52; } if (c=='+') { return 62; } if (c=='/') { return 63; } return -1; } public String encode(byte[] aSource) { int result_length = aSource.length*4/3 + (aSource.length%3==0?0:1); char result[]=new char[ ((aSource.length+2)/3)*4 ]; int o_ofs=0; int i_ofs=0; while (i_ofs<aSource.length) { int i24=0; for (int bscan=0;bscan<3;bscan++) { if (i_ofs>=aSource.length) { i24=i24<<8; } else { i24=(i24<<8)+(aSource[i_ofs]&0xff); } i_ofs++; } if (o_ofs<result_length) result[o_ofs++]=sBase64[(i24>>18)&63]; if (o_ofs<result_length) result[o_ofs++]=sBase64[(i24>>12)&63]; if (o_ofs<result_length) result[o_ofs++]=sBase64[(i24>>6)&63]; if (o_ofs<result_length) result[o_ofs++]=sBase64[(i24)&63]; } while (o_ofs<result.length) result[o_ofs++]='='; return new String(result); } } } </code></pre> I got exception: <pre><code>javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher </code></pre> at line: <pre><code>final byte[] plainText = decipher.doFinal(message); </code></pre> in decrypt method. My test method: <pre><code> public static void main(String args[]) throws Exception { DESHelper des = new DESHelper(); String encryptedStr = des.encrypt("admin", "admin"); DESHelper.Base64 base64 = des.new Base64(); System.out.println("Encrypted String: " + encryptedStr); System.out.println("Decrypted String" + des.decrypt(encryptedStr.getBytes(), "admin")); } </code></pre> Maybe I missing something? Correct me if I have something wrong. Thanks
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Decrypt password with salt using 3DES
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