Q. Explain the Bit-Level Encryption?

Bit-Level Encryption

- Data is divided into blocks of bits then altered by encoding/decoding, permutation, substitution, exclusive OR, rotation, and so on

- Encoding/decoding - decoder changes an input of n bits into an output of 2n bits; encoder has 2n outputs and only n outputs

- Permutation - transposition at the bit level

- Straight permutation - number of bits in input and output are preserved

- Compressed permutation - number of bits is reduced

- Expanded permutation - number of bits is increased

- May be implemented in hardware circuitry to be performed very quickly (referred to as P-boxes)