Cryptography is both the practice and the study of hiding
information. It has been used for centuries to secure secret documents.Today, advanced cryptographic methods are utilized in different approaches to guarantee secure communications. The components of the cryptography are authentication, integrity, and confidentiality
Symmetric Key Algorithms
Symmetric encryption algorithms are best known as shared-secret key
algorithms. Furthermore, it utilizes only one key , called a shared-secret for both encrypting and decrypting. This is a simple, easy to-utilize technique for encryption.
Examples of symmetric encryption algorithms are DES, 3DES, AES, IDEA,
RC2/4/5/6, and Blowfish.
DES
Data Encryption Standard (DES) is a block cipher algorithm that takes plain blocks in blocks of 64 bits and changes over them to ciphertext using keys of 48 bits. It is a symmetric key algorithm, which implies that a similar key is utilized for encrypting and decrypting data.
3DES
3DES is 256 times stronger than DES. It takes a 64-bit block of data. And it performs three iterations of DES operations.
- Encrypts, decrypts, and encrypts.
- Requires extra processing time.
- Can use 1, 2, or 3 distinct keys
AES
AES is an iterative rather than the Feistel cipher. It depends on ‘substitution permutation network’. It includes a series of linked tasks, some of which include replacing inputs by specific outputs (substitutions) and others include shuffling bits around (permutations). It utilizes 10 rounds for 128-bit keys, 12 rounds for 192-bit keys and 14 rounds for 256-bit keys. Every one of these rounds utilizes a different 128-bit round key, which is determined from the original AES key.
RC4
It is a stream symmetric cipher. RC4 works by making long keystream sequences and adding them to data bytes.
It encrypts data by adding it XOR byte by byte, consistently, to keystream bytes. The entire RC4 algorithm depends on making keystream bytes. The keystream is received from a 1-d table called the T table.
RC5
In RC5 algorithm, the input plain text bloc size, number of rounds and 8-bit bytes of the key can be of variable length. When the values of this are chosen, the values will continue as before for a specific execution of the cryptographic algorithm. Size of the plain text block can be of 32 bits, 64 bits or 138 bits. Length of the key can be of 0 to 2040 bits. The yield created by RC5 is the ciphertext which has the size equivalent to plain text size.
In the RC5 algorithm, the plain text message is partitioned into two blocks A and B every one of 32 bits. Then two subkeys are produced S[0] and S[1]. These two subkeys are included into A and B respectively. This procedure produces C and D respectively and marks the finish of the one-time activity. After that the procedure of the round starts. In each round, the following operation performed.
- Bitwise XOR.
- Left circular shift.
- addition to the next subkey, for both C and D. This, is the addition operation, and then the result of addition mod 2^w is performed.
Blowfish
Blowfish is a symmetric block cipher that can be utilized as a drop-in replacement for DES or IDEA. It take a variable-length key, from 32 bits to 448 bits, making it perfect for both domestic and exportable use. Blowfish was planned in 1993 by Bruce Schneier as a quick, free option in contrast to existing encryption algorithms. From that point forward it has been dissected extensively, and it is gradually picking up acknowledgment as a solid encryption algorithm. Blowfish is unpatented and permit free, and is accessible free for anyone.
