Self-dual cyclic codes over Z4 of length 4n.

For any odd positive integer n, we express cyclic codes over Z 4 of length 4n in a new way. Based on the expression of each cyclic code C , we provide an efficient encoder and determine the type of C . In particular, we give an explicit representation and enumeration for all distinct self-dual cyclic codes over Z 4 of length 4n and correct a mistake in the paper "Concatenated structure of cyclic codes over Z 4 of length 4n" (Cao et al. in Appl Algebra Eng Commun Comput 10:279–302, 2016). In addition, we obtain 50 new self-dual cyclic codes over Z 4 of length 28. [ABSTRACT FROM AUTHOR]