  This paper suggests a message authentication scheme, which can be efficiently
used for secure digital signature creation. The algorithm used here is an
adjusted union of the concepts which underlie projective geometry and group
structure on circles. The authentication is done through a key, which iterates
over the complete message string to produce the signature. The iteration is not
only based on the frequency distribution of the message string alphabet, but
also on the probability of occurrence of another given reference string in the
message. The complete process can be easily computed in a small time, producing
signatures which are highly dependent on the message string. Consequently, the
odds in favor of existence of a forgery are highly reduced.
