Secret key Algorithms in Cryptography
Cryptography is the are of that deal with creating methods to assure that messages are secretly sent and received. In Cryptography the techniques which are use to protect information using mathematical algorithms to convert messages in ways that make it hard to decode it. These algorithms are used to protect data privacy, web browsing on internet and to protect confidential transactions. Features Of Cryptography are Confidentiality, Integrity, Non-repudiation, Authentication.
Symmetric key algorithms
A symmetric algorithm (secret algorithm) is a cryptographic algorithm that uses the same key to encrypt and decrypt data. Symmetric key algorithms tend to be very secure. In general, they are considered more secure than asymmetric key algorithms.Symmetric key algorithms are also very fast. So This use to encrypt a lot of data.
There are so many symmetric key algorithms available. Each has its own strengths and weaknesses. Some of the more common examples are DES, 3DES, AES, RC4, and RC5. Let’s discuss about some common symmetric key algorithms.
DES
It is the Data Encryption Standard. DES was originally Developed in 1976. It has been one of the most widely used encryption algorithms. DES is a block Cipher, which means that it takes a fixed-length string of plaintext bits and transforms it through a series of complicated operations. This fixed-length of plaintext is of 64-bits, and the key which is the same for both encryption and decryption is also of 64-bits. The original DES standard uses a 56-bit encryption key. Actually, the initial key consists of 64 bits. However, before the DES process even starts, every 8th bit of the key is discarded to produce a 56 bit key. That is bit position 8, 16, 24, 32, 40, 48, 56 and 64 are discarded. The DES algorithm itself is very strong. Nowadays, computers are much faster. So, it may take a day or so to run through all the combinations. Therefore DES is not widely used to data encryption.
3DES
It is most commonly known as Triple DES. 3DES gets its name because it applies the DES algorithm three times to each block of data. DES has both a 64-bit block and key size, but in practice, the key only grants 56-bits of security. 3DES was developed as a more secure alternative because of DES’s small key length. In 3DES, the DES algorithm is run through three times with three keys, however it is only considered secure if three separate keys are used.Once the weaknesses of normal DES became more apparent, 3DES was adopted in a wide range of applications. It was one of the more commonly used encryption schemes before the rise of AES.
AES
It is the Advanced Encryption Standard.The AES standard actually includes three different ciphers: AES-128, AES-192, and AES-256. The numbers represent the length of the encryption key. AES is very fast and very secure.
RC4
It is the fourth version of the Rivest Cipher. RC4 uses a variable length encryption key. This key can vary from 40 to 256 bits. It’s most commonly used with a 128-bit key. The RC4 algorithm is very simple and easy to implement. RC4 has been one of the mostly widely used encryption algorithms. It is used in WEP and WPA on wireless networks. It has also been used in Secure Sockets Layer (SSL) and Transport Layer Security (TLS) with the Hypertext Transfer Protocol over SSL (HTTPS) protocol.