Package com.cedarsoftware.util

Class EncryptionUtilities

java.lang.Object

com.cedarsoftware.util.EncryptionUtilities

public class EncryptionUtilities
extends Object

Useful encryption utilities that simplify tasks like getting an encrypted String return value (or MD5 hash String) for String or Stream input.

Author:

John DeRegnaucourt ([email protected])
Copyright (c) Cedar Software LLC

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.

Method Summary

Modifier and Type	Method	Description
static String	calculateHash(MessageDigest d, byte[] bytes)	Calculate a hash String from the passed in byte[].
static String	calculateMD5Hash(byte[] bytes)	Calculate an MD5 Hash String from the passed in byte[].
static String	calculateMD5Hash(FileChannel ch)
static String	calculateSHA1Hash(byte[] bytes)	Calculate an MD5 Hash String from the passed in byte[].
static String	calculateSHA256Hash(byte[] bytes)	Calculate an SHA-256 Hash String from the passed in byte[].
static String	calculateSHA512Hash(byte[] bytes)	Calculate an SHA-512 Hash String from the passed in byte[].
static Cipher	createAesCipher(String key, int mode)
static Cipher	createAesCipher(Key key, int mode)	Creates a Cipher from the passed in key, using the passed in mode.
static Cipher	createAesDecryptionCipher(String key)
static Cipher	createAesEncryptionCipher(String key)
static byte[]	createCipherBytes(String key, int bitsNeeded)
static String	decrypt(String key, String hexStr)	Get unencrypted String from encrypted hex String
static byte[]	decryptBytes(String key, String hexStr)	Get unencrypted byte[] from encrypted hex String
static String	encrypt(String key, String content)	Get hex String of content String encrypted.
static String	encryptBytes(String key, byte[] content)
static String	fastMD5(File file)	Super-fast MD5 calculation from entire file.
static MessageDigest	getDigest(String digest)
static MessageDigest	getMD5Digest()
static MessageDigest	getSHA1Digest()
static MessageDigest	getSHA256Digest()
static MessageDigest	getSHA512Digest()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

fastMD5

public static String fastMD5(File file)

Super-fast MD5 calculation from entire file. Uses FileChannel and direct ByteBuffer (internal JVM memory).

Parameters:

file - File that from which to compute the MD5

Returns:

String MD5 value.

calculateMD5Hash

public static String calculateMD5Hash(FileChannel ch)
                               throws IOException

Throws:

IOException

calculateMD5Hash

public static String calculateMD5Hash(byte[] bytes)

Calculate an MD5 Hash String from the passed in byte[].

Parameters:

bytes - byte[] for which to obtain the MD5 hash.

Returns:

String of hex digits representing MD5 hash.

getDigest

public static MessageDigest getDigest(String digest)

getMD5Digest

public static MessageDigest getMD5Digest()

calculateSHA1Hash

public static String calculateSHA1Hash(byte[] bytes)

Calculate an MD5 Hash String from the passed in byte[].

Parameters:

bytes - byte[] of bytes for which to compute the SHA1

Returns:

the SHA-1 as a String of HEX digits

getSHA1Digest

public static MessageDigest getSHA1Digest()

calculateSHA256Hash

public static String calculateSHA256Hash(byte[] bytes)

Calculate an SHA-256 Hash String from the passed in byte[].

Parameters:

bytes - byte[] for which to compute the SHA-2 (SHA-256)

Returns:

the SHA-2 as a String of HEX digits

getSHA256Digest

public static MessageDigest getSHA256Digest()

calculateSHA512Hash

public static String calculateSHA512Hash(byte[] bytes)

Calculate an SHA-512 Hash String from the passed in byte[].

Parameters:

bytes - byte[] for which to compute the SHA-3 (SHA-512)

Returns:

the SHA-3 as a String of HEX digits

getSHA512Digest

public static MessageDigest getSHA512Digest()

createCipherBytes

public static byte[] createCipherBytes(String key,
                                       int bitsNeeded)

createAesEncryptionCipher

public static Cipher createAesEncryptionCipher(String key)
                                        throws Exception

Throws:

Exception

createAesDecryptionCipher

public static Cipher createAesDecryptionCipher(String key)
                                        throws Exception

Throws:

Exception

createAesCipher

public static Cipher createAesCipher(String key,
                                     int mode)
                              throws Exception

Throws:

Exception

createAesCipher

public static Cipher createAesCipher(Key key,
                                     int mode)
                              throws Exception

Creates a Cipher from the passed in key, using the passed in mode.

Parameters:

key - SecretKeySpec

mode - Cipher.ENCRYPT_MODE or Cipher.DECRYPT_MODE

Returns:

Cipher instance created with the passed in key and mode.

Throws:

Exception - if the requested Cipher instance does not exist.

encrypt

public static String encrypt(String key,
                             String content)

Get hex String of content String encrypted.

Parameters:

key - String value of the encryption key (passphrase)

content - String value of the content to be encrypted using the passed in encryption key

Returns:

String of the encrypted content (HEX characters), using AES-128

encryptBytes

public static String encryptBytes(String key,
                                  byte[] content)

decrypt

public static String decrypt(String key,
                             String hexStr)

Get unencrypted String from encrypted hex String

Parameters:

key - String encryption key that was used to encryption the passed in hexStr of characters.

hexStr - String encrypted bytes (as a HEX string)

Returns:

String of original content, decrypted using the passed in encryption/decryption key against the passed in hex String.

decryptBytes

public static byte[] decryptBytes(String key,
                                  String hexStr)

Get unencrypted byte[] from encrypted hex String

Parameters:

key - String encryption/decryption key

hexStr - String of HEX bytes that were encrypted with an encryption key

Returns:

byte[] of original bytes (if the same key to encrypt the bytes was passed to decrypt the bytes).

calculateHash

public static String calculateHash(MessageDigest d,
                                   byte[] bytes)

Calculate a hash String from the passed in byte[].

Parameters:

d - MessageDigest to update with the passed in bytes

bytes - byte[] of bytes to hash

Returns:

String hash of the passed in MessageDigest, after being updated with the passed in bytes, as a HEX string.