# Important Symmetric and Assymmetric Encryption Algorithms

### Symmetric Encryption Algorithms

Before continuing, click the following link to learn what is Symmetric Encryption and Assymetric Encryption, if you are not familiar with the terms Symmetric Encryption and Assymetric Encryption.

Data Encryption Standard (DES): Data Encryption Standard (DES) is an early data encryption algorithm that encrypts data with a 56-bit, randomly generated symmetric key to encrypt/decrypt 64-bit blocks of data. Data Encryption Standard (DES) was developed by IBM and the U.S. Government together and was published in 1975. DES is a block encryption algorithm.

DES is no more a secure encryption algorithm and it was cracked many times. In 1999 an organization called distributed.net, combined the idle time of 100,000 PCs on the Internet to crack a DES key in 23 hours. Read more details from below links.

http://www.distributed.net/DES

http://lasec.epfl.ch/memo/memo_des.shtml#ref7

3DES: 3DES (Pronounced as "Triple DES") was developed from DES, uses a 64-bit key consisting of 56 effective key bits and 8 parity bits. In 3DES, DES encryption is applied three times to the Clear-Text. The Clear-Text is encrypted with Key A, decrypted with Key B, and encrypted again with Key C. 3DES is a block encryption algorithm. 3DES is still a stronger Symmetric Encryption Algorithm and it is far secure than Data Encryption Standard (DES).

3DES Encryption and Decryption process using three different Keys are as listed below

• Encrypt with Key A
• Decrypt with Key B
• Encrypt with Key C

Decryption process is just the reverse of encryption process

• Decrypt with Key C
• Encrypt with Key B
• Decrypt with Key A

Refer the following link for a high-level technical view of 3DES

Advanced Encryption Standard (AES): Advanced Encryption Standard (AES) is a newer and stronger encryption standard, which uses the Rijndael (pronounced Rhine-doll) algorithm. Rijndael algorithm was developed by Joan Daemen and Vincent Rijmen of Belgium. AES will eventually displace DESX and 3DES. AES is capable to use 128-bit, 192-bit, and 256-bit keys. Advanced Encryption Standard (AES) is the most secure symmetric encryption algorithm, when comparing DES and 3DES.

Refer the following link for a high-level technical view of Advanced Encryption Standard (AES)

### Assymmetric Encryption Algorithm

Rivest Shamir Adleman (RSA): Ron Rivest, Adi Shamir, and Len Adleman released the Rivest-Shamir-Adleman (RSA) public key algorithm in 1978. This algorithm can be used for encrypting and signing data. The encryption and signing processes are performed through a series of modular multiplications.

RSA is the most widely used Assymmetric Encryption Algorithm. Most widely used network security protocols like SSH (Secure Shell), OpenPGP, SSL/TLS etc are built on top of RSA and rely on RSA for encryption and digital signature functions.

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