Cryptography

Techopedia explains Cryptography

Information security uses cryptography on several levels. The information cannot be read without a key to decrypt it. The information maintains its integrity during transit and while being stored. Cryptography also aids in non-repudiation. This means that neither the creator nor the receiver of the information may claim they did not create or receive it. Cryptography also allows senders and receivers to authenticate each other through the use of key pairs.

There are various types of algorithms for encryption:

• Secret Key Cryptography (SKC): Here only one key is used for both encryption and decryption. This type of encryption is also referred to as symmetric encryption.
• Public Key Cryptography (PKC): Here two keys are used. This type of encryption is also called asymmetric encryption. One key is the public key and anyone can have access to it. The other key is the private key, and only the owner can access it. The sender encrypts the information using the receiver’s public key. The receiver decrypts the message using his/her private key. For non-repudiation, the sender encrypts plain text using a private key, while the receiver uses the sender’s public key to decrypt it. Thus, the receiver knows who sent it.
• Hash Functions: These are different from SKC and PKC. They have no key at all and are also called one-way encryption. Hash functions are mainly used to ensure that a file has remained unchanged.