Encryption is a process of how to maintain the security of a message or file by encoding the messages or information in a way that eavesdroppers or hackers cannot read it, but can only be read by authorized personnel. Encryption also is the process of translating the plain text data (plaintext) into something that appears to be random and meaningless (ciphertext).
Encryption is also used to protect data in transit, for example data being transferred via networks (e.g. the Internet, e-commerce), mobile telephones, wireless microphones,wireless intercom systems, Bluetooth devices and bank automatic teller machines.
To encrypt and decrypt data, you must use a key with an encryption algorithm that performs a transformation on the data. The .NET Framework provides several classes that enable you to perform cryptographic transformations on data using several standard algorithms.
Generating Keys for Encryption and Decryption
Creating and managing keys is an important part of the cryptographic process. Symmetric algorithms require the creation of a key and an initialization vector (IV). The key must be kept secret from anyone who should not decrypt your data. The IV does not have to be secret, but should be changed for each session. Asymmetric algorithms require the creation of a public key and a private key. The public key can be made public to anyone, while the private key must known only by the party who will decrypt the data encrypted with the public key. This section describes how to generate and manage keys for both symmetric and asymmetric algorithms.
Encrypting Data
Symmetric encryption and asymmetric encryption are performed using different processes. Symmetric encryption is performed on streams and is therefore useful to encrypt large amounts of data. Asymmetric encryption is performed on a small number of bytes and is therefore useful only for small amounts of data.
Decryption
Decryption is
the process of taking encoded or encrypted text or other data and converting it
back into text that you or the computer are able to read and understand. This
term could be used to describe a method of un-encrypting the data manually or with
un-encrypting the data using the proper codes or keys.
Decrypting Data
Decryption is
the reverse operation of encryption. For secret-key encryption, you must know
both the key and IV that were used to encrypt the data. For public-key
encryption, you must know either the public key (if the data was encrypted
using the private key) or the private key (if the data was encrypted using the
public key).
