Test Flashcards
Key people behind RSA
Ron Rivest, Adi Shamir, and Leonard Adleman
RSA was publicly described the algorithm in
1977
Applications and use cases of rsa
- Digital Signatures
- Digital Certificates
- Secure Communication Protocols
- Secure Key Exchange
Blowfish designed by (name) in (year)
Bruce Schneier
1993
Blowfish have (number) of bit
64-bit
It is significantly faster than DES and provides a good encryption rate with no effective cryptanalysis technique found to date.
Blowfish Key Exchange
The Blowfish encryption algorithm is suitable for use in scenarios where a fast, secure, and freely available encryption technique is needed. Some common use cases include:
- Data Encryption
- Network Security
- Software Protection
Blowfish PROS
Fast
Resilient
Open
Blowfish CONS
Blocksize
3DES SECURITY FEATURES:
- Triple DES ( 3 DES) is a symmetric encryption algorithm based on the Data Encryption Standard ( DES).
- It uses three successive DES operations ( encrypt- decrypt- encrypt) to achieve enhanced security.
3DES KEY SECURITY ASPECTS:
- Key Length: Uses three 56 - bit keys ( 168 bits total) for encryption, making brute- force attacks computationally infeasible.
- Key Variability: Offers keying options ( e. g., all three keys are independent or two keys are the same) to adapt to different security requirements.
- Block Size: Operates on 64 - bit blocks, which provides a larger data block size compared to DES.
ADVANTAGE OF TRIPLE DES:
- Robust Security: Provides a higher level of security compared to single DES due to the triple encryption process.
- Backward Compatibility: Maintains compatibility with existing DES implementations and infrastructure.
- Widely Adopted: Still widely used in legacy systems and environments where stronger encryption standards are required.
DES stands for
Data Encryption Standard
DES algorithm uses a key of
56-bit size
DES is a block cipher with (number) rounds of (Name) structure
16
Feistel
In 2002, it was overthrown by AES, which became the new standard following a public competition.
DES (Data Encryption Standard)
The AES Encryption algorithm also
known as the
Rijndael algorithm
AES is a symmetric block ciper algorithm with a block/chunk size of
128 bits
features of AES
- SP NETWORK
- KEY EXPANSION
- BYTE DATA
- KEY LENGTH
It works on an SP network structure rather than a Feistel cipher
structure, as seen in the case of the DES algorithm.
SP NETWORK (feature of AES)
It takes a single key up during the first stage, which is later
expanded to multiple keys used in individual rounds.
KEY EXPANSION (feature of AES)
The AES encryption algorithm does operations on byte data
instead of bit data. So it treats the 128-bit block size as 16 bytes
during the encryption procedure.
BYTE DATA (feature of AES)
The number of rounds to be carried out depends on the length of the key being used to encrypt data. The 128-bit key size has ten rounds, the 192-bit 04 key size has 12 rounds, and the 256-bit key size has 14 rounds.
KEY LENGTH (feature of AES)
4 STEPS OF AES ENCRYPTION
ALGORITHM
- Sub Bytes
- Shift Rows
- Mix Columns
- Add Round Key
Operates on the state array by first converting each byte into its hexadecimal
representation.
SubByte (steps of aes algorithm)
Performs a cyclic shift on the last three rows of a state
matrix.
ShiftRows (steps in aes algorithm)
Operates by multiplying a constant matrix with each column in the current state array.
Mix Columns (steps in aes algorithm)
The algorithm performs a bitwise XOR operation between
the current state array, obtained from the prior step, and a key specific to the current round.
Add Round Key (steps in aes algorithm)
A cryptographic
protocol that allows two parties to establish a shared
secret key over an insecure communication channel.
Diffie-Hellman key exchange
Why cryptography protocols are needed
for secure communication?
- Confidentiality
- Integrity
- Authentication
- Non-repudiation
- Key exchange
Diffie Hellman Key Exchange was invented by (name) and (name) in (year)
Whitfield Diffie and Martin Hellman
in 1976
Key Exchange Process
- Parameter Selection
- Private Key Generation
- Public Key Computation
- Public Key Exchange
- Shared Secret Key Computation
- Shared Secret Key
Security Features of Diffie Hellman Key exchange
- Perfect Forward Secrecy
- Protection Against Eavesdropping
- Key Exchanged without Pre-shared keys
- Resistance to Man-in-the-Middle Attacks
- Computational Complexity
- Flexibility
Applications of Diffie - Hellman
- Secure Communication
- Key Establishment for Symmetric Encryption
- VPN (Virtual Private Network) Protocols
- SSH (Secure Shell) Protocol
- Wireless Communication Security
- Digital Signatures and Key Agreement
- Secure Messaging Protocols
Diffie Hellman Key Exchange Limitations
- Man-in-the-middle attacks
- Vulnerabilities in specific implementations
- Forward Secrecy
Who invented Hill Cipher and in what year
Lester S. Hill
1929
First polygraphic cipher
Hill Cipher
Polygraphic substitution cipher based on linear algebra
Hill Cipher
Each letter is represented by modulo 26
Hill Cipher
Advantage of Hill Cipher
- Perfectly conceals single-letter frequencies
- Easily solvable when dealing with 2x2 matrices
- Useful when hiding a single-letter or two-letter frequency information
- High diffusion and strong tamper resistance without detection
- It can withstand any attack, except if the attack is through a known plaintext
Disadvantages of Hill Cipher
- Vulnerable to know-plaintext attacks
- A simple 2x2 matrix is quite simple. Still, when it expands, the calculations to encrypt or decrypt the data become much more complex, requiring a deep understanding of higher mathematics
