Digesters

Digesters are classes specialized in creating message digests from input.

Message digests are the results of hash functions, and they are unidirectional, this is, starting from a message digest, the original message cannot be reconstructed.

Because of this, message digests are very adequate for password encryption. In fact, in some countries, it is illegal to store a user's password in an unencrypted way, and even encrypted in a reversible (bi-directional) way.

Digesters in jasypt live in the org.jasypt.digest package, which is composed of the following interfaces:

• ByteDigester for creating digests from byte array input.
• StringDigester for creating digests from String input.

And the following default implementations:

• StandardByteDigester: very configurable and extremely secure implementation of ByteDigester, implemented following the directives given in PKCS #5: Password-Based Cryptography Standard.
• StandardStringDigester: String counterpart to StandardByteDigester, receiving String input and returning charset-safe, BASE64 (or hexadecimal) encoded String output.

It's basic usage can be very simple:

...
StandardStringDigester digester = new StandardStringDigester();
digester.setAlgorithm("SHA-1");   // optionally set the algorithm
digester.setIterations("50000");  // increase security by performing 50000 hashing iterations
...
String digest = digester.digest(myMessage);
...

Standard*Digesters implement a coherent and secure set of default configuration values, but they can be additionally configured in two ways:

• By calling to its setX(...) methods (algorithm, provider, salt size, etc.)
• By setting a DigesterConfig object which configures the digester. A default bean implementation of this interface is supplied (SimpleDigesterConfig), but the user can create his/her own one to be able to retrieve configuration parameters in whichever ways he/she needs.

Please refer to the JavaDoc for more information about usage and functionality.

Encryptors

Encryptors are classes specialized in performing bi-directional encryption operations. This is, they can both encrypt plain data and decrypt encrypted data.

The relevant interfaces for encryption in jasypt live in the org.jasypt.encryption package, and are:

• ByteEncryptor for encryption and decryption of byte arrays.
• StringEncryptor for encryption and decryption of Strings.
• BigIntegerEncryptor for encryption and decryption of BigIntegers.
• BigDecimalEncryptor for encryption and decryption of BigDecimals.

Jasypt provides implementations for one type of encryption: Password-Based Encryption (PBE).

...
StandardPBEStringEncryptor encryptor = new StandardPBEStringEncryptor();
encryptor.setPassword("jasypt");                     // we HAVE TO set a password
encryptor.setAlgorithm("PBEWithMD5AndTripleDES");    // optionally set the algorithm
...
String encryptedText = encryptor.encrypt(myText);
...
String plainText = encryptor.decrypt(encryptedText);  // encryptedText.equals(plainText)
...