Cryptography

The three most common types of cryptography: symmetric key, asymmetric key systems and cryptographic hash functions. Symmetric key uses the same key to encrypt and decrypt a message. Common forms of symmetric encryption include: data encryption standard (DES), Triple DES, Blowfish and Advanced Encryption Standard (AES). DES is the least secure because it only has 56-bit key, which is small compared to the other symmetric keys, triple DES-168, 112 or 56, Blowfish-32-448, or AES 128, 192 or 256 (Schmeh, 2003, pp. 76). Generally the longer the key, the stronger the encryption. Asymmetric cryptography is also known as public-key encryption. It requires two separate keys for encryption and decryption, one key is a secret or private key and the other key is a public key. The public key is used to encrypt the text and the private key is used decrypt the encrypted text which is also called ciphertext. Some popular asymmetric encryption techniques are Rivest-Shamir-Adleman (RSA), and Diffie-Hellman. Hash functions are sometimes referred to one-way encryption. They have no key; they use a fixed length hash value. Used mostly to ensure message integrity it provides a digital fingerprint of a messages content. This ensures that the message has not been altered. Hashing algorithms have a very low probability that two messages would create the same hash value. Most common hashing algorithms are: MD-Message Digest and SHA-secure hashing algorithm.

Cryptographic techniques are used to address issues with confidentiality, integrity and authenticity. Confidentiality refers to preventing disclosure of information to unauthorized recipients, including other computer systems. For example, using encryption during transmission of messages ensures even if the message is intercepted, without the encryption/decryption key, then message can’t be read. Hashing algorithms help ensure integrity of messages. Using message digests generated by hashing technicians can detect...