From the course: Symmetric Cryptography Essential Training
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Cipher block chaining (CBC)
From the course: Symmetric Cryptography Essential Training
Cipher block chaining (CBC)
- [Instructor] In cipher block chaining mode, usually called CBC, the cipher text output from the previous block is XORed with the plaintext. This is the mode that I used when I demonstrated AES and DES from the command line. CBC mode relies on having complete blocks to work properly. Some sort of padding will be necessary to make this happen. When you use cipher block chaining, you don't have the ability to encrypt the plaintext in parallel. You can, however, decrypt the ciphertext in parallel, and that gives you the ability to have random read access to the ciphertext. You can decrypt different parts from the ciphertext without having to start from the beginning. When an error occurs in the plaintext, that will affect many of the following ciphertext blocks. But when it's decrypted, only that original error will appear, so it's not really that much of a problem. Cipher text errors corrupt both the corresponding plaintext block and the next one, too, but not any after that. Any after…
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