javax.crypto.Cipher - The Secret Key Encryption Class

JDK Tutorials - Herong's Tutorial Examples - Version 6.02, by Dr. Herong Yang

JDK Tutorials - Herong's Tutorial Examples

∟Cipher - Secret Key Encryption and Decryption

∟javax.crypto.Cipher - The Secret Key Encryption Class

This section provides a quick introduction of the cipher class, javax.crypto.Cipher, to encrypt input data with a secret key.

In the previous chapter, I learned how to use classes and interfaces in the JCE (Java Cryptography Extension) package to generate and manage secret keys. Now I am ready to learn how to use secret keys to encrypt or cipher any input data using the javax.crypto.Cipher class.

javax.crypto.Cipher is a class that provides functionality of a cryptographic cipher for encryption and decryption. It has the following major methods.

getInstance() - Returns a Cipher object of the specified transformation (algorithm plus options) from the implementation of the specified provider. If provider is not specified, the default implementation is used. This is a static method.

init() - Initializes this cipher for the specified operation mode with the specified key or public key certificate. Two important operation modes are Cipher.ENCRYPT_MODE and Cipher.DECRYPT_MODE.

update() - Feeds additional input data to this cipher and generates partial output data.

doFinal() - Feeds the last part of the input data to this cipher and generates the last part of the output data.

getBlockSize() - Returns the block size of this cipher.

getAlgorithm() - Returns the algorithm name of this cipher.

getProvider() - Returns the provider as a Provider object of this cipher.

See the next section how to use the javax.crypto.Cipher class in a sample program.

Last update: 2014.

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