Fingerprinting

Fingerprinting is a special application of watermarking that applies specifically to information that is embedded about the creator of the work or the recipient. Fingerprinting has the characteristics of one object that distinguish it from another, very similar object. The real-world use of digital fingerprinting enables owners to trace authorized users distributing their material illegally. It can also be used as a means of high-speed searching.

Fingerprinting Examples

• Human

• Fired bullet

• Serial number

• Coded particles of explosives

• Maps

Digital Fingerprints

• Prefixes of e-mail addresses

• PGP public keys

• Digital audio or video

• Documents

Terminology

• Mark: A portion of an object with a set of several possible states

• Fingerprint: A collection of marks

• Distributor: An authorized provider of fingerprinted objects

• Authorized user: An individual who is authorized to gain access to a fingerprinted object

• Attacker: Someone who gains unauthorized access to fingerprinted objects

• Traitor: An authorized user who distributes fingerprinted objects illegally

• Labeling: Where embedded data contains information of interest, such as a unique identifier

Fingerprinting Classification

• Object-based classification

  • Physical fingerprinting is where an object has characteristics that can be used to differentiate it from something else.

  • Digital fingerprinting is a fingerprint in a form that a computer can process.

• Detection-sensitivity-based classification

  • Perfect fingerprinting is any alteration that makes the fingerprint unrecognizable.

  • Statistical fingerprinting allows an examiner to compare fingerprint alterations to confidently determine that a compromised user has been identified.

  • Threshold fingerprinting allows for a certain number of illegal uses, but when that number is reached or passed, it identifies it as an illegal copy.

• Fingerprinting-method-based classification

  • Recognition: Human fingerprints.

  • Deletion: A portion of the original object is deleted.

  • Addition: A new portion is added to the original object.

  • Modification: A deliberate change to some portion of the object is made for identification.

• Fingerprint-based classification

  • Discrete: The fingerprint has a finite hash value.

• Continuous: The fingerprint has an infinite value, a human fingerprint.