New Idea to Prolong Period of Sequence

In order to get long period pseudo-random sequence, the new composite idea to prolong periods of sequences is brought out. The composite idea prolongs period of sequences with a few short period sequences through compound operation. The new idea was proven, and applications were introduced in the paper. The result shows that the longer period may be gotten by compound idea. The conclusions are that the new idea is effective, rightly, simple for cipher and the compound sequence is more secure to enforce information security.