PGP Functions

PGP offers the following functions:

• Digital signatures and verification of messages' integrity: function based on the simultaneous use of a hash function (MD5) and the RSA system. MD5 hashes the message and produces a 128-bit result that is then encrypted, thanks to RSA, by the sender's private key.
• Local file encryption: function using IDEA.
• Generation of public or private keys: each user encrypts his messages using IDEA private keys. The transfer of IDEA electronic keys uses the RSA system; PGP therefore offers key-generation devices adapted to this system. The size of RSA keys is proposed according to several security levels: 512, 768, 1024 or 1280 bits.
• Key management: function responsible for distributing the user's public key to the correspondents wanting to send him encrypted messages.
• Key certification: this function makes it possible to add a digital seal guaranteeing the authenticity of public keys. It is an original feature of PGP, which bases its trust on a notion of social proximity rather than on the central certification authority.

Revoking, disabling, and registering of keys: function that makes it possible to produce revocation certificates.