An RSA public key consists of a modulus n and an exponent e. Modulus n is a product of two large primes, p and q. If one knows p or q, one can derive the private key corresponding to the given public key.
A typical GPG public key contains one or more RSA moduli, depending on the number of sub-keys.
Under certain conditions, a public key modulus will share a common factor with an existing modulus belonging to someone else. This may happen if both keys were generated on a system with a thoroughly-broken entropy source, or if a particular GPG implementation has been back-doored.
Comments
Nah, it just found a weak key bug. A very embarrassing weak key bug, but not one that breaks RSA.
Disclaimer: I'm not a cryptographer, I have very possibly misread the article. Corrections welcome.
From http://nosuchlabs.com/theory
An RSA public key consists of a modulus n and an exponent e. Modulus n is a product of two large primes, p and q. If one knows p or q, one can derive the private key corresponding to the given public key.
A typical GPG public key contains one or more RSA moduli, depending on the number of sub-keys.
Under certain conditions, a public key modulus will share a common factor with an existing modulus belonging to someone else. This may happen if both keys were generated on a system with a thoroughly-broken entropy source, or if a particular GPG implementation has been back-doored.