How does encryption work?
Essentially the plaintext is combined with a mathematical algorithm (a set of rules for processing data) such that the original text cannot be deduced from the output file, hence the data is now in encrypted form. To enable the process to be secure, a key is combined with this algorithm. This key might be a personal key for your own use or it might be a system generated session key. In this case, you will never need to know the key. It is only used for one session then discarded. A new key will be generated for the next session. Generally a personal key will be used again and again and need the protection of a passphrase. Some programs offer a choice of both a passphrase or a keyfile or both may be used together. Obviously the process must be reversible, but only with the aid of the correct key. Without the key, the process should be extremely difficult. The mathematics of the encryption should be openly available for peer review.
Essentially the plaintext is combined with a mathematical algorithm(a set of rules for processing data) such that the original textcannot be deduced from the output file, hence the data is now inencrypted form. To enable the process to be secure, a key (calledthe passphrase) is combined with this algorithm. Obviously theprocess must be reversible, but only with the aid of the correct key.Without the key, the process shouldbe extremely difficult. Themathematics of the encryption should be openly available for peerreview. At first sight this may appear to compromize the encryption,but this is far from the case.
There are many types of encryption but the basic concept is to encode information (data) so that only those with the right “key” can decode and use it. For PGP, your “key” is the password you enter when you turn on your laptop. For an excellent (but lengthy) explanation of how encryption in general and PGP in particular work, visit PGP Intro.
Encryption works by encoding the text of a message with a key. In traditional encryption systems, the same key was used for both encoding and decoding. In the new public key or asymmetric encryption systems, keys come in pairs: one key is used for encoding and another for decoding. In this system everyone owns a unique pair of keys. One of the keys, called the public key, is widely distributed and used for encoding messages. The other key, called the private key, is a closely held secret used to decrypt incoming message. Under this system, a person who needs to send a message to a second person can encrypt the message with that person’s public key. The message can only be decrypted by the owner of the secret private key, making it safe from interception. This system can also be used to create unforgeable digital signatures. Most practical implementations of secure Internet encryption actually combine the traditional symmetric and the new asymmetric schemes. Public key encryption is use
On the Internet, there are two main uses for encryption. One occurs when you visit a “secure” Website, such as an online store or shopping mall. This is called server-side encryption because it uses the Server Certificate given to the server (computer) that runs the Website. The other use occurs when you send or receive encrypted e-mail. In both cases, the encryption process involves exchanging public keys. When encrypting information, the encryption process involves a public and a private key. Think of it as a lock that requires one key to close the lock and another key to open the lock. For example, when you visit a secure Website, your computer receives the Website’s public key. When your computer sends information to the Website, your computer encrypts it using the Website’s public key. The only way to decrypt the information you are sending is with the Website’s private key.
