GNU Privacy Guard

PGP is a cryptosystem developed by Phil Zimmerman, as a way to combat an attempt by the FBI to trick people into using the Clipper Chip, which was designed to have a back door for law enforcement agencies. Since then, PGP has become a popular method of encrypting and digitally signing documents and email.

Unlike the familiar Certificate Authority system used for TLS and S/MIME, PGP uses a web of trust. People meet each other to verify public key signatures, often at "key signing parties", and then sign public keys (using their private keys). Some people choose to upload their public key, with others' signatures, to "key servers", which help to automate the process of exchanging keys. If a person chooses to "marginally" trust a key, then that key can be used to help establish the authenticity of a public key that is has been used to sign; if three marginally trusted keys have been used to sign a single key, that key is considered verified by the web of trust (but this is only allowed up to two levels). In this way, it is possible for a key that has not been directly verified to be trusted.

GnuPG is a popular libre implementation of PGP, which is shipped with most major GNU/Linux distributions and BSDs. Although Thunderbird does not directly support GPG or PGP, the Enigmail plugin can be used to add support.

Good crypto method savinf the our anonimyty.

See also

• Verifying PGP Signatures
• Maximum security with gpg‎
• How to protect your email using Tor
• PGP Tutorial for Windows