Java tutorial
/* * Copyright 2016 JBoss Inc * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package io.apiman.common.util; import java.security.InvalidKeyException; import java.security.NoSuchAlgorithmException; import java.util.HashMap; import java.util.Map; import javax.crypto.BadPaddingException; import javax.crypto.Cipher; import javax.crypto.IllegalBlockSizeException; import javax.crypto.NoSuchPaddingException; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.codec.binary.Base64; /** * A simple AES encrypter. * * @author eric.wittmann@redhat.com * @author Rachel Yordn <ryordan@redhat.com> */ public class AesEncrypter { private static final String secretKey = "f2f0aa80-84bd8a6"; //$NON-NLS-1$ private static final Map<String, SecretKeySpec> keySpecs = new HashMap<>(); /** * Constructor. */ private AesEncrypter() { } /** * Encrypt. * @param plainText the plain text * @return the string */ public static String encrypt(String plainText) { return encrypt(secretKey, plainText); } /** * Encrypt. * @param plainText the plain text * @param secretKey the secret key * @return the string */ public static String encrypt(String secretKey, String plainText) { if (plainText == null) { return null; } byte[] encrypted; Cipher cipher; try { SecretKeySpec skeySpec = keySpecFromSecretKey(secretKey); cipher = Cipher.getInstance("AES"); //$NON-NLS-1$ cipher.init(Cipher.ENCRYPT_MODE, skeySpec); } catch (NoSuchAlgorithmException e) { throw new RuntimeException(e); } catch (NoSuchPaddingException e) { throw new RuntimeException(e); } catch (InvalidKeyException e) { throw new RuntimeException(e); } try { encrypted = cipher.doFinal(plainText.getBytes()); } catch (IllegalBlockSizeException e) { throw new RuntimeException(e); } catch (BadPaddingException e) { throw new RuntimeException(e); } return "$CRYPT::" + new String(Base64.encodeBase64(encrypted)); //$NON-NLS-1$ } /** * Returns a {@link SecretKeySpec} given a secret key. * @param secretKey */ private static SecretKeySpec keySpecFromSecretKey(String secretKey) { if (!keySpecs.containsKey(secretKey)) { byte[] ivraw = secretKey.getBytes(); SecretKeySpec skeySpec = new SecretKeySpec(ivraw, "AES"); //$NON-NLS-1$ keySpecs.put(secretKey, skeySpec); } return keySpecs.get(secretKey); } /** * Decrypt. * @param encryptedText the encrypted text * @return the string */ public static final String decrypt(String encryptedText) { return decrypt(secretKey, encryptedText); } /** * Decrypt. * @param encryptedText the encrypted text * @param secretKey the secret key * @return the string */ public static final String decrypt(String secretKey, String encryptedText) { if (encryptedText == null) { return null; } if (encryptedText.startsWith("$CRYPT::")) { //$NON-NLS-1$ byte[] decoded = Base64.decodeBase64(encryptedText.substring(8)); Cipher cipher; try { SecretKeySpec skeySpec = keySpecFromSecretKey(secretKey); cipher = Cipher.getInstance("AES"); //$NON-NLS-1$ cipher.init(Cipher.DECRYPT_MODE, skeySpec); } catch (NoSuchAlgorithmException e) { throw new RuntimeException(e); } catch (NoSuchPaddingException e) { throw new RuntimeException(e); } catch (InvalidKeyException e) { throw new RuntimeException(e); } try { String decryptedString = new String(cipher.doFinal(decoded)); return decryptedString; } catch (IllegalBlockSizeException e) { throw new RuntimeException(e); } catch (BadPaddingException e) { throw new RuntimeException(e); } } else { return encryptedText; } } /** * Main entry point for the encrypter. Allows encryption and decryption of text * from the command line. * @param args */ public static final void main(String[] args) { if (args.length != 2) { printUsage(); return; } String cmd = args[0]; String input = args[1]; if ("encrypt".equals(cmd)) { //$NON-NLS-1$ System.out.println(AesEncrypter.encrypt(input).substring("$CRYPT::".length())); //$NON-NLS-1$ } else if ("decrypt".equals(cmd)) { //$NON-NLS-1$ System.out.println(AesEncrypter.decrypt("$CRYPT::" + input)); //$NON-NLS-1$ } else { printUsage(); } } /** * Usage. */ @SuppressWarnings("nls") private static void printUsage() { System.out.println("Usage:"); System.out.println("\tAesEncrypter encrypt|decrypt \"input\"\n------"); System.out.println("Argument 1: the command, either 'encrypt' or 'decrypt'"); System.out.println("Argument 2: the text to encrypt or decrypt (use quotes if the input contains spaces)"); System.out.println(""); } }