A given cipher can be used in a variety of modes. Modes allow you to specify how encryption will work.

For example, you can allow the encryption of one block to be dependent on the encryption of the previous block, or you can make the encryption of one block independent of any other blocks.

The mode you choose depends on your needs and you must consider the trade-offs (security, ability to parallel process, and tolerance to errors in both the plaintext and the ciphertext). Selection of modes is beyond the scope of this tutorial (see Resources for further reading), but again, for your information, the Java platform supports the following modes:

• ECB (Electronic Code Book)
• CBC (Cipher Block Chaining)
• CFB (Cipher Feedback Mode)
• OFB (Output Feedback Mode)
• PCBC (Propagating Cipher Block Chaining)