Complete Guide to Stream Cipher

Stream Cipher: is a method in cryptography where plaintext is combined with a cipher digit by digit. Unlike block ciphers that encrypt blocks of plaintext, Stream Cipher encrypts plaintext symbols one at a time. Stream ciphers fall under the category of symmetric key cipher where the same key is used for both encryption and decryption.

Importance: Due to its ability to encrypt data one bit at a time, it provides high security for data transmission. Its efficient performance in hardware and suitability for encrypting large data makes it highly valuable. Furthermore, it assures confidentiality and maintains the integrity of data.

How it works: Stream Cipher uses a pseudo-random cipher digit generator to generate a stream of bits, which is then combined with the plaintext bit-by-bit or byte-by-byte to produce the ciphertext. The process is reversed during decryption using the same pseudo-random sequence.

Exam Tips: Understanding the mechanism of Stream Cipher is vital for exams.
Consider the following:
* Highlight the difference between a block cipher and a stream cipher.
* Clearly understand the use of pseudo-random number generator in the process.
* Highlight the pros and cons of using Stream Cipher.
* Be able to describe how Stream Cipher ensures data security.