Prerequisites: 62:160 and 62:171 both with "C+" or better grade or 62:160 and 62:181 both with "C+" or better grade.

An introduction to number theory and its application to cryptography. The topics in number theory include congruencies, residues, Fermat"s Theorem, Chinese Remainder Theorem, tests for primality and Galois Fields.

Some simple ciphers and their history will be discussed followed by a careful study of the RSA public key encryption scheme, the knapsack cipher and the Data Encryption Standard.

3 lecture hours per term , one term

Transfer Equivalents: Look up 62:265 in the BU Course Transfer Database.