Cryptography Basics
Common Encryption Algorithms included
DES - DES is a block cipher with 64-bit block size and uses 56-bit keys.
Triple DES - Triple DES or 3DES was designed as a more secure and stronger encryption algorithm to replace the original version of DES algorithm. Triple DES encrypts the data three times with three different individual keys of 56-bits each, which makes the total cumulative key length up to 112-168 bits long.
RSA - RSA is a public-key encryption algorithm and a standard for encrypting sensitive data sent over an insecure network like the Internet.
AES - AES encryption algorithm comprises of three block ciphers of 128-bits, 192-bits and 256-bits. Although encryption with AES 128-bits is quite strong and efficient, 192-bits and 256-bits key is used for higher grade of encryption.
AES is a symmetric encryption algorithm and uses a single private-key for both encryption and decryption processes. AES encryption algorithm is used by numerous organizations worldwide apart from being trusted by the US government.
Blowfish - Blowfish has a 64-bit block size and a variable key length from 32-bits up to 448-bits. Blowfish encryption algorithm splits a message into the blocks of 64-bits and then encrypts the blocks individually.
Twofish -
MD5 - MD5 is a one-way hash function which creates a 128-bit hash value, and is most commonly used in digital signature applications.
MD5 algorithm has been optimized for 32-bit machines and was designed to replace MD4, an earlier hash function also designed by Rivest.
MD5 algorithm verifies data integrity by processing a variable-length message into a fixed-length output hash of 128-bits. MD5 algorithm is sometimes also referred to as Message-Digest algorithm.
SHA - SHA or Secure Hash Algorithm is a family of cryptographic functions which includes SHA-0, SHA-1, SHA-2 and SHA-3.
SHA-1 cryptographic hash function that was designed by the United States’ NSA in 1995. However, SHA-1 is no longer considered to secure enough and post 2010 many cyber-security experts have recommended the use of SHA-2 or SHA-3 as a replacement to SHA-1. Most of the popular browsers would stop the support for SHA-1 based SSL certificates.
SHA-2 is also designed by NSA and was first published in 2001. SHA-2 is a set of cryptographic hash functions which includes six hash functions of different digest sizes: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, and SHA-512/256.
SHA-3, was approved by National Institutes of Standards and Technology (NIST) as a part of a competition which received 64 submissions from all over the world. Subsequently, SHA-3 standard was released by NIST in August 2015.
HMAC - HMAC or Hash-based Message Authentication Code (HMAC), first published in 1996, is a type of message authentication code that involves both a secret cryptographic key and hash function. HMAC simultaneously verifies the data integrity and authenticates the message.
In HMAC, the message and the key are hashed in separate steps which adds to the security of HMAC. The cryptographic strength of HMAC is dependent on the strength and size of the hash function and size of the key.
IPSec and TLS protocols use HMAC-SHA1 and HMAC-MD5 encryption algorithms.