  This article proposes the use of pseudorandom decimal sequences that have
gone through an additional random mapping for the design of cryptographic keys.
These sequences are generated by starting with inverse prime expansions in base
3 and then replacing 2 in the expansion with either the string 01 or 10 based
on the preceding bit, which represents a general mapping. We show that the
resulting pseudorandom sequences have excellent autocorrelation properties.
Such a method can be extended to inverse prime expansions to any base.
