JNCryptor
JNCryptor is an easy-to-use library for encrypting data with AES. It was ported to Java from the RNCryptor library for iOS.
News
| Date | News |
|---|---|
| 2014-01-19 | Version 1.0.1 released. Fixes issue #4, which caused the wrong version number to be output in some situations. |
| 2014-01-13 | Version 1.0.0 released. This version is more streamlined, with no external dependencies. The previously deprecated factory classes are now removed. |
| 2014-01-13 | Projected moved to GitHub. |
| 2014-01-07 | Version 0.5 released. This version supports v3 of the RNCryptor format, which was necessary due to a bug in the objective-c implementation (see original issue here). This new version of JNCryptor deprecates the factory-style method of creating instances in favour of a new class, AES256JNCryptor. See the documentation for more details. |
| 2013-12-27 | Version 0.4 released. Now the number of PBKDF iterations can be set. Note: read the caution below before considering using variable iterations. |
| 2013-02-28 | Version 0.3 released. Fixes an issue where spaces in the path to the JAR caused the factory to fail. |
| 2013-02-03 | Version 0.2 released. No functionality changes, however the dependencies are now correctly contained in the binary downloads. |
| 2013-01-31 | Version 0.1 released. |
Getting JNCryptor
You can download binaries, documentation and source from the Releases page. Maven users can copy the following snippet to retrieve the artifacts from Maven Central:
<dependency>
<groupId>org.cryptonode.jncryptor</groupId>
<artifactId>jncryptor</artifactId>
<version>1.0.1</version>
</dependency>
The Javadocs can also be browsed online (TODO).
Using JNCryptor
A quick example is shown below:
JNCryptor cryptor = new AES256JNCryptor();
byte[] plaintext = "Hello, World!".getBytes();
String password = "secretsquirrel";
try {
byte[] ciphertext = cryptor.encryptData(plaintext, password.toCharArray());
} catch (CryptorException e) {
// Something went wrong
e.printStackTrace();
}
Iterations
JNCryptor supports changing the number of PBKDF2 iterations performed by the library. Unfortunately, the number of iterations is not currently encoded in the data format, which means that both sides of the conversation need to know how many iterations have been used.
There are plans afoot to include the ieration count in the data format (hopefully in v4). Until that time, use these feature with caution.
Android
JNCryptor can be used in Android applications. Download the latest binary release and place the JAR in the libs folder for your project.
Please note that very little Android testing has been completed and some users report compatibility problems with old versions of Android (see the Issues page). If I can find an easy way to do so, I'll start increasing my Android testing and improve the library accordingly.
Data Format
A proprietary data format is used that stores the IV, salt values (if applicable), ciphertext and HMAC value in a compact fashion. Methods are offered to encrypt data based on either an existing key, or a password. In the latter case, a key is derived from the password using a key derivation function, with 10,000 iterations and a salt valu.e
See the spec documents online.
Keys are derived from the password and the appropriate salt value using the PBKDF2 function with SHA1. A separate key is generated for encrypting the plaintext and computing the HMAC.
History
The data format supported by this library is v3. Both v1 and v0 have a significant security flaw whereby only the ciphertext was included in the HMAC value. There are no plans to support v1 or v0. v2 was deprecated due to a multi-byte password issue discovered in the objective-c implementation.