"A stream cipher is a symmetric key cipher where plaintext digits are combined with a pseudorandom cipher digit stream (keystream)."
A type of encryption that encrypts data one bit or byte at a time.
Cryptography Basics: Understanding the basics of cryptography, including its history, terminology, and applications.
Symmetric Cryptography: Understanding symmetric encryption techniques and how they are used in stream ciphers.
Encryption Algorithms: Understanding stream cipher encryption algorithms such as RC4, A5/1, and ChaCha.
Key Generation: Understanding key generation processes for stream ciphers, including key scheduling and initialization.
Block and Stream Ciphers: Understanding the difference between block and stream ciphers and how to choose the right type for different use cases.
Advantages and Disadvantages: Understanding the pros and cons of using stream ciphers, including performance, security, and implementation considerations.
Security Analysis: Understanding how to evaluate the security of stream cipher algorithms, including common attacks such as brute force, differential cryptanalysis, and side-channel attacks.
Cryptographic Protocols: Understanding how stream ciphers are used in cryptographic protocols such as SSL/TLS, VPN, and SSH.
Key Management: Understanding how to securely manage cryptographic keys, including key exchange and key rotation.
Implementation: Understanding how to implement stream ciphers in software and hardware, and how to optimize performance while maintaining security.
XOR Stream Cipher: This is a simple stream cipher that uses the XOR operation to encrypt and decrypt data, with the key being a random stream of bits.
LFSR Stream Cipher: This cipher uses a Linear Feedback Shift Register (LFSR) to generate a pseudo-random stream of bits that is used as the key for encrypting and decrypting data.
RC4 Stream Cipher: This is a widely used stream cipher that generates a pseudo-random stream of bytes based on a secret key, which is then used to encrypt and decrypt data.
A5/1 Stream Cipher: This is a cipher used in mobile phone networks, which uses three LFSRs to generate different pseudo-random sequences that are combined to form a key stream.
Salsa20 Stream Cipher: This is a secure and efficient stream cipher that uses a 64-bit nonce and a 256-bit key to generate a stream of pseudorandom bytes.
ChaCha20 Stream Cipher: This is a variant of the Salsa20 cipher that uses a different permutation function to generate the pseudorandom stream.
Grain Stream Cipher: This cipher uses a combination of feedback shift registers and non-linear feedback functions to generate a stream of pseudo-random bits that are used to encrypt and decrypt data.
Trivium Stream Cipher: This is a cipher that uses three LFSRs and a non-linear feedback function to generate a stream of pseudo-random bits that is used as the key for encryption and decryption.
Panama Stream Cipher: This cipher uses a key-dependent permutation and a nonlinear feedback function to generate a stream of pseudo-random bits that are used to encrypt and decrypt data.
ISAAC Stream Cipher: This cipher uses a cryptographic hash function to generate a stream of pseudo-random bits that is used to encrypt and decrypt data.
Rabbit Stream Cipher: This is a stream cipher based on the RC4 algorithm, which uses a nonlinear feedback function to generate a stream of pseudorandom bits.
HC-128 Stream Cipher: This is a stream cipher that uses a 128-bit secret key and a 128-bit initialization vector (IV) to generate a stream of pseudo-random bits.
Grain-128a Stream Cipher: This is a variant of the Grain cipher that uses a 128-bit key and an initialization vector (IV) to generate a stream of pseudo-random bits.
MICKEY Stream Cipher: This is a stream cipher that uses a combination of LFSRs and a non-linear feedback function to generate a stream of pseudo-random bits.
Helix Stream Cipher: This cipher uses a feedback shift register and a non-linear function to generate a stream of pseudo-random bits that are used for encryption and decryption.
"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 a state cipher."
"The combining operation is an exclusive-or (XOR)."
"The pseudorandom keystream is typically generated serially from a random seed value using digital shift registers."
"The seed value serves as the cryptographic key for decrypting the ciphertext stream."
"Stream ciphers represent a different approach to symmetric encryption from block ciphers. Block ciphers operate on large blocks of digits with a fixed, unvarying transformation."
"This distinction is not always clear-cut: in some modes of operation, a block cipher primitive is used in such a way that it acts effectively as a stream cipher."
"Stream ciphers typically execute at a higher speed than block ciphers and have lower hardware complexity."
"Yes, stream ciphers can be susceptible to security breaches."
"Stream ciphers can be susceptible to security breaches (see stream cipher attacks)."
"For example, when the same starting state (seed) is used twice."
"The pseudorandom keystream is typically generated serially from a random seed value."
"The pseudorandom keystream is typically generated serially from a random seed value using digital shift registers."
"The seed value serves as the cryptographic key for decrypting the ciphertext stream."
"The combining operation is an exclusive-or (XOR)."
"Stream ciphers typically execute at a higher speed than block ciphers."
"Stream ciphers typically execute at a higher speed than block ciphers and have lower hardware complexity."
"In some modes of operation, a block cipher primitive is used in such a way that it acts effectively as a stream cipher."
"Stream ciphers typically execute at a higher speed than block ciphers and have lower hardware complexity."