The triple-DES (DES3 ) is a variation of DES in which three 64-bit keys are

used for a 19 2-bit key. DES3 works by first encrypting the plain text by

using the first 64-bits of the key. Then the ciphertext is decrypted by using

the next part of the key. In the final step, the resulting ciphertext is re-

encrypted by using the last part of the key.

The Advanced Encryption Standard (AES) is a replacement algorithm

that is used by the U nited States Government.

The cipher modes are symmetric, asymmetric, block, and stream.

Symmetric ciphers

For encryption of plaintext and decryption of ciphertext, the symmetric

ciphers use the same cryptographic keys. These ciphers are fast and allow

encrypting of large sets of data. Secret keys to both parties should be

securely distributed, which requires sophisticated mechanisms.

This encryption involves only one secret key to cipher and deciphers

information.

A number, a word, or a string of random letters are used as a secret key in

symmetrical encryption. To change the content in a particular way, blending

with the plaintext of a message is done. The secret key used to encrypt and

decrypt all the messages should be known by the sender and the recipient.

Examples of symmetric encryption are Blowfish, AES, RC4, DES, RC5 ,

and RC6.

All parties involved have to exchange the key used to encrypt the data

before they can decrypt it, which is a disadvantage of this encryption

scheme.

Asymmetric ciphers

Also known as public-key cryptography, it uses two keys to encrypt a

plaintext. Internet or a network is used to exchange secret keys, which

ensures that malicious persons do not misuse the keys. Note that anyone

with a secret key can decrypt the message, which is the reason why

asymmetrical encryption uses two related keys to boost security. For anyone

who might want to send you a message, a public key is made freely