PGP (Pretty Good Privacy)

Project Synopsis

Project Title: PGP (Pretty Good Privacy)

Tools / Platform: The project will be in Windows-2000 platform with ASP .Net (Scripting to be done using C#). The Web Server will be IIS. SQL server 2000 will be used as the back end device.

Introduction to application Area

PGP means "Pretty Good Privacy" and is an application used to crypt messages. This is the most famous application for crypting personal data such as letters, emails, a file or anything else you can find on a computer; because it is very powerful and has been developed on almost all existing computers (PC, Macintosh, Amiga, etc). In fact, it is the first application that has been developed for public as a pose to military use. It is maybe why PGP is becoming a standard application on computers.

When you have English text and you want to translate it into French, you use language translation. In this case, any French person could read your new text and understand it. However, if you have the same English text but you do not want anybody else, except yourself, to be able to understand it, you use cryptography.

Cryptography has been used for a very long time; the roman emperor Cesar is the first famous person who used it for his military campaigns. These last few years the army has mainly used it but since the computer has become a common tool, cryptography is used and needed by everyone.

Each country has different laws about the use of cryptography for various reasons, because in some country the use of strong cryptography is illegal, it is a sensitive subject that makes it really interesting and in a way, dangerous. Because fact that more and more companies wants to sell products on the Internet, the cryptography status is changing to allow the customers to secure their transactions.

Algorithms

Many different cryptography algorithms have been done, but there are two main algorithms used in cryptography. Here is a general overview of these two cryptography standards.

1. Private key algorithm

A private key algorithm uses one password (or one private key) to crypt a message, to decrypt it the same password is used, the same algorithm or a different one can be used to crypt and decrypt.

2. Public key algorithm

A public key algorithm consists of a public key (B) used to crypt a message and a private key (A) used to decrypt the message, for one public key there is one private key (A1, B1) and only the private key that belongs to the public key can decrypt a message crypted by the public key.

This algorithm can also be used to sign a message to prove that it is really you who is sending a message, to do so you crypt the message with your private key that can be decrypted only with the public key. This is a bit difficult to understand, but just means that if you crypt a message with one of the keys (public or private) you can decrypt it only with the other key; if someone wants to imitate your signature he will fail because he will crypt his message with your public key, but as this message can only be decrypted with the private key, nobody will be able to decrypt it. This feature is really useful in business or for the army.