Encryption is the process of turning data into an unreadable form using cryptographic algorithms. The data will remain unreadable by humans until it is unencrypted back into plain text. The three primary encryption methods are hashing, symmetric, and asymmetric.

Secure Hash Algorithm(SHA)
Secure hash algorithm or SHA was designed to secure hashing algorithms and to keep the integrity of the data/message. SHA has 4 variations.



* SHA-0: The first version of SHA created in 1993; uses a 160-bit hash function. It was not used long if was soon replaced with the more secure SHA-1 due to a security flaw.
* SHA-1: This version uses the 160-bit hash function that was designed by the NSA to be part of digital signatures.
* SHA-2: This version has two different functions that work the same just have different block sizes. SHA-256(256-bit) SHA-512(512-bit) which are more secure and harder to crack then its originals.
* SHA-3: This version is going to be released in 2012 and is suppose to be very strong and build off its previous versions weaknesses.


Message Digest Algorithm
Message digest algorithm(MDA)was designed to secure hashing algorithm and to keep the integrity of the data/message. There are a few different versions coming off of MDA.

* MD2: Released in 1989 this encryption is 128-bit and is used with public keys or certificates.
* MD4: Released in 1990 this encryption is 128-bit, SHA-1 sprouted of its concept. It is not used with security because it is very susceptible to attacks. It is used for file identification (checksums).
* MD5: Released in 1992 this encryption is 128-bit this is commonly used for security in alot of applications, and used to check the integrity of files MD5 Check Sum.
* MD6: Released in 2008 and might transform into the future SHA-3.


Symmetric Algorithms
This function requires a key at the start of encryption and when it decrypts it. Without a key encryption/decryption is not possible. It generates a secret key sometimes known as a private key. Only people authorised to access the encryption system would know the private key. If the private key is disclosed the files encrypted with that key would be susceptible to being compromised. Some commonly used examples would be TwoFish, AES, IDEA, Blowfish, Serpent and many many others.

Asymmetric Algorithms
This function uses two keys to encrypt and decrypt data, those keys are known as “Public” and “Private”. Unlike symmetric systems that require 1 key for encryption and decryption with this an encrypter can use the public key then the receiver or decrypter would use the private key to decrypt the contents. The private key is only known by the owner, and one of the keys during the encryption/decryption process is always private, hence the public/private.

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