Encryption Technology General Information

[ Concepts ]

Plaintext
this is the original message which has not yet been encrypted(or an algorithm will applied to).

Ciphertext
This is the encrypted or scrambled message produced by applying the algorithm to the plaintext message using the secret key.

Encryption
The process of scrambling data according to a mathematical formula or algorithm so that the data is unintelligible to all but the intended recipients. In the context of security requirements, encryption enables both privacy (confidentiality of data) and access control (ensuring that the data is accessed only by those who are authorized to do so).

Decryption
The process of descrambling the encoded data to render a secret message intelligible to the intended recipients.

Cryptography
The science of encoding (encrypting) and decoding (decrypting) messages and information in secret code.

Cryptographic algorithm


Key
Formally called cryptographic key, is a sequence of symbols, represented in binary form as a string of bits, which controls the encryption algorithm (the mathematical transformation of plain text into encoded text). The relationship between encrypted messages and their keys is very much like that between locks and keys. Just as a lock can be opened only with the right key, an encrypted message can be decrypted only with the right key. The widely used U.S. Data Encryption Standard (DES) employs a 56-bit key. Generally, the longer the key, the stronger the algorithm.

Strength
One of the main points to make about electronic encryption is there are many qualities, or strengths of it. The systems range from one that's never been broken into and never will be, to encryption that looks scrambled and impenetrable to a novice, but can be broken into by an expert in seconds -- without the use of computers. The strength of encryption technology is determined by the number of bits used in the encryption process. The higher the number of bits used to encrypt, the stronger the encryption technology. For example, IDEA (128-bit key) is stronger than DES (56-bit key). This means that the DES technology would be easier to "crack."


[ How Encryption Works ]
There are two dominant forms of encryption technology that are used all over the world: Symmetric Key Encryption, and Public Key Encryption. Although they work in different ways, they both have the same functional uses.

Symmetric Key Encryption


Public Key Encryption


Practical Uses of the Two Types of Encryption
In practice, Public-Key Encryption (like RSA) is not used to encrypt messages. Public-Key Encryption is secure and convenient, but heavy on computation. Most messages would take a long time to encrypt and decrypt, even with today's computers. Instead, Public-Key Encryption is used as a secure way to send a key for a Symmetric Key Encryption (like DES and IDEA).

Example:
1. you create a file (like an e-mail message).
2. the file is encrypted using symmetric key encryption.
3. The Symmetric Key is encrypted using the receiving computer's Public Key.
4. both encrypted items (file and the Symmetric Key) are sent to the receiving computer.
5. the receiving computer use its private key to decode (decryption) the Symmetric Key.
6. the receiving computer then uses the included symmetric key to decode the original file.