What Is a PGP Signature?

PHP signatures can authenticate email messages.

Digital signatures are encoded into files, messages and documents to guarantee that the file's content is unmodified. Pretty Good Privacy, or PGP, is an encryption program that uses signatures for authentication purposes.

PGP

PGP uses data encryption and decryption to provide privacy. Data encryption involves converting digital information from a readable state to an unreadable state. To read the encrypted data, you need a key or password.

Function

A PGP digital signature allows the recipient of a PGP-encrypted message to verify that the message's content is intact and to validate the sender's identity. PGP can be set to use digital signatures automatically.

Message Digests

Before creating a digital signature for a message, the PGP program creates a hash, or message digest. A hash is a procedure that produces a short string of digital information based on the message's content. PGP then combines this hash with the user's private key to create a signature.

References

• PCmag.com: Definition of PGP
• "Secure Messaging with PGP and S/MIME"; Rolf Oppliger; 2000

Resources

• "Digital Signatures"; Ben Hammond; 2002