PGP Allows Use of Unauthorized Additional Decryption Keys

 

Reported August 23, 2000 by Ralf Senderek

VERSIONS AFFECTED

DESCRIPTION

A flaw exists in the Addition Decryption Keys (ADK) key recovery mechanisms of PGP. An attacker could insert additional decryption keys into the unsigned portion of the public key data structure, which would systematically cause any encrypted to become decryptable by anyone with knowledge of the added decryption key. 

BACKGROUND INFORMATION

Ralf Sederek's paper "How PGP Deals with Manipulated Keys"

"The Risks Of 'Key Recovery,' 'Key Escrow,' And 'Trusted Third-Party' Encryption" by Hal Abelson, Ross Anderson, Steven M. Bellovin, Josh Benaloh, Matt Blaze, Whitfield Diffie, John Gilmore, Peter G. Neumann, Ronald L. Rivest, Jeffrey I. Schiller, and Bruce Schneier.

Series of technical responses mirrored at Cryptome.

VENDOR RESPONSE

Network Associates is aware of the problem, however no response was known at the time of this writing. 

CREDIT
Discovered by Ralf Senderek