In cryptography

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

, a key signing party is an event at which people present their PGP

Pretty Good Privacy

Pretty Good Privacy is a data encryption and decryption computer program that provides cryptographic privacy and authentication for data communication. PGP is often used for signing, encrypting and decrypting texts, E-mails, files, directories and whole disk partitions to increase the security...

-compatible key

Key (cryptography)

In cryptography, a key is a piece of information that determines the functional output of a cryptographic algorithm or cipher. Without a key, the algorithm would produce no useful result. In encryption, a key specifies the particular transformation of plaintext into ciphertext, or vice versa...

s to others in person, who, if they are confident the key actually belongs to the person who claims it, digitally sign

Digital signature

A digital signature or digital signature scheme is a mathematical scheme for demonstrating the authenticity of a digital message or document. A valid digital signature gives a recipient reason to believe that the message was created by a known sender, and that it was not altered in transit...

 the PGP certificate containing that public key and the person's name, etc. This is one way to strengthen the web of trust

Web of trust

In cryptography, a web of trust is a concept used in PGP, GnuPG, and other OpenPGP-compatible systems to establish the authenticity of the binding between a public key and its owner. Its decentralized trust model is an alternative to the centralized trust model of a public key infrastructure ,...

.

Although PGP keys are generally used with personal computer

Personal computer

A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...

s for Internet

Internet

The Internet is a global system of interconnected computer networks that use the standard Internet protocol suite to serve billions of users worldwide...

-related applications, key signing parties themselves generally do not involve computers, since that would give adversaries increased opportunities for subterfuge. Rather, participants write down a string of letters and numbers, called a public key fingerprint

Public key fingerprint

In public-key cryptography, a public key fingerprint is a short sequence of bytes used to authenticate or look up a longer public key. Fingerprints are created by applying a cryptographic hash function to a public key...

, which represents their key. The fingerprint is created by a cryptographic hash function

Cryptographic hash function

A cryptographic hash function is a deterministic procedure that takes an arbitrary block of data and returns a fixed-size bit string, the hash value, such that an accidental or intentional change to the data will change the hash value...

, which condenses the public key down to a string which is shorter and more manageable. Participants exchange these fingerprints as they verify each others' identification. Then, after the party, they obtain the public keys corresponding to the fingerprints they received and digitally sign them.

People can bring their identity document

Identity document

An identity document is any document which may be used to verify aspects of a person's personal identity. If issued in the form of a small, mostly standard-sized card, it is usually called an identity card...

s to a key signing party.

External links

• Keysigning Party Howto
• Biglumber – Keysigning coordination website
• keysigning.org – Key signing party coordination website