Exam SY0-501 topic 1 question 763 discussion

Block cipher works on chunks of data, encrypting one and then moving to the next.In stream cipher, the data is encrypted one bit, or byte, at a time. CompTIA security+ Study Guide 7th Edition

c is correct In stream cipher, one byte is encrypted at a time while in block cipher ~128 bits are encrypted at a time. Initially, a key(k) will be supplied as input to pseudorandom bit generator and then it produces a random 8-bit output which is treated as keystream. The resulted keystream will be of size 1 byte, i.e., 8 bits. Stream Cipher follows the sequence of pseudorandom number stream. One of the benefits of following stream cipher is to make cryptanalysis more difficult, so the number of bits chosen in the Keystream must be long in order to make cryptanalysis more difficult. By making the key more longer it is also safe against brute force attacks. The longer the key the stronger security is achieved, preventing any attack. Keystream can be designed more efficiently by including more number of 1s and 0s, for making cryptanalysis more difficult. Considerable benefit of a stream cipher is, it requires few lines of code compared to block cipher.

A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream). In a stream cipher, each plaintext digit is encrypted one at a time with the corresponding digit of the keystream, to give a digit of the ciphertext stream. Since encryption of each digit is dependent on the current state of the cipher, it is also known as state ciph

transmit data bit by bit

Option C is correct