Java in a Nutshell, 5th Edition

Name

Cipher

Synopsis

This class performs encryption and decryption of byte arrays. Cipher is provider-based, so to obtain a Cipher object, you must call the static getInstance( ) factory method. The arguments to getInstance( ) are a string that describes the type of encryption desired and, optionally, the name of the provider whose implementation should be used. To specify the desired type of encryption, you can simply specify the name of an encryption algorithm, such as “DES”. In Java 5.0, the “SunJCE” provider supports the following algorithm names:

AES	DES	RSA
AESWrap	DESede	PBEWithMD5AndDES
ARCFOUR	DESedeWrap	PBEWithMD5AndTripleDES
Blowfish	RC2	PBEWithSHA1AndRC2_40

Advanced users may specify a three-part algorithm name that includes the encryption algorithm, the algorithm operating mode, and the padding scheme. These three parts are separated by slash characters, as in “DES/CBC/PKCS5Padding”. Finally, if you are requesting a block cipher algorithm in a stream mode, you can specify the number of bits to be processed at a time by following the name of the feedback mode with a number of bits. For example: “DES/CFB8/NoPadding”. Details of supported operating modes and padding schemes are beyond the scope of this book. In Java 5.0, you can obtain details about the services available through the SunJCE (or any other) provider through the java.security.Provider.Services class.

Once you have obtained a Cipher object for the desired cryptographic algorithm, mode, and padding ...