  Personal Identification Numbers (PINs) are commonly used as an authentication
mechanism. An important security requirement is that PINs should be hard to
guess for an attacker. On the other hand, remembering several random PINs can
be difficult task for an individual. We evaluate several dictionary-based
methods of choosing a PIN. We experimentally show that these methods are far
from ideal with respect to expected covering of the PIN space and the entropy
of PINs. We also discuss two methods for constructing easy to memorize PIN
words for randomly chosen PINs.
