Performance Evaluation of Various Symmetric and Asymmetric Cryptosystems for Variable Text Size

Internet and networks application are growing very fast, so the need to protect such application are increased by using cryptographic methods. Many encryption algorithms are widely available and used in information security. They can be categorized into Symmetric (private) and Asymmetric (public) key encryption. Symmetric key ciphers use the same key for encryption and decryption, or the key used for decryption is easily calculated from the key used for encryption. Symmetric key ciphers can be broadly grouped into block ciphers and stream ciphers. Symmetric encryption has a troublesome drawback i. e. , two people who wish to exchange confidential messages must share a secret key. The key must be exchanged in a secure way. Key distribution is difficult among the parties. One thing common to all private key cryptosystems is that if one knows how to cipher a message then he automatically knows how to decipher the message. Thus the method of ciphering must be kept secret. Once the ciphering method is compromised the cryptosystem is useless. Thus this cryptosystem is less secure but having high speed therefore frequently used for sending bulk messages. The ideas of the public key cryptosystems was first introduced by Diffie and Hellman [2] in 1976. Since then, several different protocols for public key cryptography have been presented e. g. RSA, ECC etc. Public key cryptosystems are highly secure but having less speed as compared to private key cryptosystems. Therefore generally used for sending short messages like secret keys. This paper presents the comparative study of some most popular Symmetric cryptosystems i. e. RC4, DES, 3DES, AES, Blowfish and some popular Asymmetric cryptosystems i. e. RSA, RSA PKCS1, RSA SAEP+, RSA OAEP, RSA OAEP+, React RSA, Hybrid React RSA and NTRU. These algorithms are compared on the basis of simulation time required for key generation, encryption and decryption for variable sized text data as input and the results were observed, analyzed and compared so as to identify which method is appropriate to the business needs.