Unless a user has a secret key, encryption denies users any access to an encrypted file. Only knowledge of the secret key allows that user the access to decrypt the encrypted file. Encryption comes in two categories, symmetric encryption and asymmetric encryption. Symmetric encryption Symmetric encryption allows both Alice (sender) and Bob (receiver) to encrypt and decrypt data using a shared key via a secret channel. Two types of symmetric encryption algorithms are stream ciphers and block ciphers. Symmetric encryption algorithms are highly effective at processing large quantities information and require less time/power to process through a CPU in comparison to asymmetric encryption techniques. However, shared key should be altered frequently, kept secure and distributed carefully as they can be cracked via brute force attack, once this key is then identified communication can be compromised. Stream Cipher Stream ciphers are naturally faster than block clock ciphers Block Cipher Block ciphers require more memory Types of Symmetric encryption DES Data Encryption Standard (DES) cipher is an outdated symmetric encryption method that uses a 56 bit algorithm and one key to encrypt and decrypt. Due to the increase in computer processing power DES can be deciphered by using the brute force attack. 3DES Triple DES is a block cipher that had been enhanced due to the DES being susceptible to brute force attacks. Triple DES used the same algorithm as the DES cipher. However, it uses a key length of 168 bits opposed to the previous 56 bit length DES utilizes. This was achieved by enlarging the key space of 3DES to three times the size of the outdated 56 bit Des and resulted in greater protect against attack. RC2 RC2 all so known as Rons Code and Rivest Cipher is a 64 bit block cipher, key size can vary from 40 to 128 bits by incrementing by 8. Rijndae Asymmetric encryption Asymmetric encryption allows both Alice (sender) and Bob (receiver) to encrypt and decrypt data via two separate keys, one key being used to encrypt and the second to decrypt. Due to using to these two keys, asymmetric encryption doesn't require a secret channel when sending out the public key as the private key is also needed to decrypt. Disadvantage is the amount of CPU power and time to process the encryption and decryption of the communication. Types of Asymmetric encryption RSA RSA generates two keys, a public and private key. These keys are based on large prime numbers that are mathematically related. The public key is shared to the public whereas the private key is kept secret. RSA keys are 1024 to 2048 bits long and provides encryption and digital signature functions for protocols such as SSH, SSL/TLS as well as browsers. AES Advanced Encryption standard was to replace DES. AES is a block cipher that uses a 256 bit key and encrypts data in blocks of 128 bits. Bluefish Blowfish is a commonly used algorithm due to no unauthorised user being able to successfully decrypt. The secret key cipher encrypts the variable numbers of bits ranging from 16 to 448 bits sixteen times. Diffie Hellmon key exchange Diffie Hellmon key exchange method allows both Alice (sender) and Bob (receiver) to create a shared secret key together over an insecure channel having no previous familiarity of each other. Once this key has been created, the following communications will be encrypted using a symmetric key cipher.