A valid, acceptable signature must be unique to the person, verifiable and secure
(i.e., under the person's sole control so that one might presume from its use that
the person intended to be bound).
Effective June 21, 2004, an acceptable signature includes signature proxy alternatives
for some applications for benefits, redeterminations, and other SSA processes (see
GN 00201.015 for policy and procedures for the use of alternative signature methods).