From: Niki Roo Date: Mon, 22 Apr 2019 17:42:09 +0000 (+0200) Subject: new: crypt utils X-Git-Url: https://git.nikiroo.be/?a=commitdiff_plain;h=52e0732e1f06ddff5d69c0588bdbd937fcc52537;p=fanfix-jexer.git new: crypt utils --- diff --git a/src/be/nikiroo/utils/CryptUtils.java b/src/be/nikiroo/utils/CryptUtils.java new file mode 100644 index 0000000..ea6892b --- /dev/null +++ b/src/be/nikiroo/utils/CryptUtils.java @@ -0,0 +1,248 @@ +package be.nikiroo.utils; + +import java.io.IOException; +import java.security.InvalidKeyException; +import java.security.NoSuchAlgorithmException; + +import javax.crypto.BadPaddingException; +import javax.crypto.Cipher; +import javax.crypto.IllegalBlockSizeException; +import javax.crypto.NoSuchPaddingException; +import javax.crypto.SecretKey; +import javax.crypto.spec.SecretKeySpec; + +/** + * Small utility class to do AES encryption/decryption. + *

+ * Do not assume it is actually secure until you checked the code... + * + * @author niki + */ +public class CryptUtils { + private Cipher ecipher; + private Cipher dcipher; + + /** + * Small and leazy way to initialize a 128 bits key with {@link CryptUtils}. + *

+ * Some part of the key will be used to generate a 128 bits key and + * initialize the {@link CryptUtils}; even NULL will generate something. + *

+ * This is most probably not secure. Do not use if you actually care + * about security. + * + * @param key + * the {@link String} to use as a base for the key, can be NULL + */ + public CryptUtils(String key) { + try { + init(key2key(key)); + } catch (InvalidKeyException e) { + // We made sure that the key is correct, so nothing here + e.printStackTrace(); + } + } + + /** + * Create a new instance of {@link CryptUtils} with the given 128 bytes key. + *

+ * The key must be exactly 128 bytes long. + * + * @param bytes32 + * the 128 bits (32 bytes) of the key + * + * @throws InvalidKeyException + * if the key is not an array of 128 bytes + */ + public CryptUtils(byte[] bytes32) throws InvalidKeyException { + init(bytes32); + } + + /** + * This method required an array of 128 bytes. + * + * @param bytes32 + * the array, which must be of 128 bits (32 bytes) + * + * @throws InvalidKeyException + * if the key is not an array of 128 bits (32 bytes) + */ + private void init(byte[] bytes32) throws InvalidKeyException { + if (bytes32 == null || bytes32.length != 32) { + throw new InvalidKeyException( + "The size of the key must be of 128 bits (32 bytes), it is: " + + (bytes32 == null ? "null" : "" + bytes32.length) + + " bytes"); + } + + SecretKey key = new SecretKeySpec(bytes32, "AES"); + try { + ecipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); + dcipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); + ecipher.init(Cipher.ENCRYPT_MODE, key); + dcipher.init(Cipher.DECRYPT_MODE, key); + } catch (NoSuchAlgorithmException e) { + // Every implementation of the Java platform is required to support + // this standard Cipher transformation with 128 bits keys + e.printStackTrace(); + } catch (NoSuchPaddingException e) { + // Every implementation of the Java platform is required to support + // this standard Cipher transformation with 128 bits keys + e.printStackTrace(); + } catch (InvalidKeyException e) { + // Every implementation of the Java platform is required to support + // this standard Cipher transformation with 128 bits keys + e.printStackTrace(); + } + } + + /** + * Encrypt the data. + * + * @param data + * the data to encrypt + * + * @return the encrypted data + * + * @throws IOException + * in case of I/O error (i.e., the data is not what you assumed + * it was) + */ + public byte[] encrypt(byte[] data) throws IOException { + try { + return ecipher.doFinal(data); + } catch (IllegalBlockSizeException e) { + throw new IOException(e); + } catch (BadPaddingException e) { + throw new IOException(e); + } + } + + /** + * Encrypt the data. + * + * @param data + * the data to encrypt + * + * @return the encrypted data + * + * @throws IOException + * in case of I/O error (i.e., the data is not what you assumed + * it was) + */ + public byte[] encrypt(String data) throws IOException { + return encrypt(data.getBytes("UTF8")); + } + + /** + * Encrypt the data, then encode it into Base64. + * + * @param data + * the data to encrypt + * @param zip + * TRUE to also compress the data in GZIP format; remember that + * compressed and not-compressed content are different; you need + * to know which is which when decoding + * + * @return the encrypted data, encoded in Base64 + * + * @throws IOException + * in case of I/O error (i.e., the data is not what you assumed + * it was) + */ + public String encrypt64(String data, boolean zip) throws IOException { + return encrypt64(data.getBytes("UTF8"), zip); + } + + /** + * Encrypt the data, then encode it into Base64. + * + * @param data + * the data to encrypt + * @param zip + * TRUE to also compress the data in GZIP format; remember that + * compressed and not-compressed content are different; you need + * to know which is which when decoding + * + * @return the encrypted data, encoded in Base64 + * + * @throws IOException + * in case of I/O error (i.e., the data is not what you assumed + * it was) + */ + public String encrypt64(byte[] data, boolean zip) throws IOException { + return StringUtils.base64(encrypt(data), zip); + } + + /** + * Decode the data which is assumed to be encrypted with the same utilities. + * + * @param data + * the encrypted data to decode + * + * @return the original, decoded data + * + * @throws IOException + * in case of I/O error + */ + public byte[] decrypt(byte[] data) throws IOException { + try { + return dcipher.doFinal(data); + } catch (IllegalBlockSizeException e) { + throw new IOException(e); + } catch (BadPaddingException e) { + throw new IOException(e); + } + } + + /** + * Decode the data which is assumed to be encrypted with the same utilities + * and is a Base64 encoded value. + * + * @param data + * the encrypted data to decode in Base64 format + * @param zip + * TRUE to also uncompress the data from a GZIP format + * automatically; if set to FALSE, zipped data can be returned + * + * @return the original, decoded data + * + * @throws IOException + * in case of I/O error + */ + public byte[] decrypt64(String data, boolean zip) throws IOException { + return decrypt(StringUtils.unbase64(data, zip)); + } + + /** + * Decode the data which is assumed to be encrypted with the same utilities + * and is a Base64 encoded value, then convert it into a String (this method + * assumes the data was indeed a UTF-8 encoded {@link String}). + * + * @param data + * the encrypted data to decode in Base64 format + * @param zip + * TRUE to also uncompress the data from a GZIP format + * automatically; if set to FALSE, zipped data can be returned + * + * @return the original, decoded data + * + * @throws IOException + * in case of I/O error + */ + public String decrypt64s(String data, boolean zip) throws IOException { + return new String(decrypt(StringUtils.unbase64(data, zip)), "UTF-8"); + } + + /** + * This is probably NOT secure! + * + * @param input + * some {@link String} input + * + * @return a 128 bits key computed from the given input + */ + static private byte[] key2key(String input) { + return StringUtils.getMd5Hash(input).getBytes(); + } +}