Overview - 2023.2 English

Vitis Libraries

Release Date
2023.2 English

The Cipher Feedback (CFB) mode is a typical block cipher mode of operation using block cipher algorithm. In this version, we provide Data Encryption Standard (DES) and Advanced Encryption Standard (AES) processing ability, the cipherkey length for DES should be 64 bits, and 128/192/256 bits for AES. Another limitation is that our working mode works on units of a fixed size (64 or 128 bits for 1 block), but text in the real world has a variety of lengths. So, the last block of the text provided to this primitive must be padded to 128 bits before encryption or decryption. Although, CFB1 and CFB8 modes share the same interface with CFB128 mode, the plaintext and ciphertext is processed bit-by-bit or byte-by-byte not block-by-block for CFB1 and CFB8 modes respectively.