FF3 - Tweak Fix about fpe

[raj-jain]

NIST is in the process of revising SP 800-38G to address the FF3 vulnerability reported previously. In a nut shell, FF3 will be revised to FF3-1 that has a smaller tweak size compared to FF3. Also, both FF1 and FF3-1 will now support a minimum domain size of 1 million (raised from 100).

https://csrc.nist.gov/news/2019/nist-requests-comments-on-draft-sp-800-38g-rev-1
https://csrc.nist.gov/publications/detail/sp/800-38g/rev-1/draft

The proposal above is in final call in NIST which is ending on 4/15/19.

[anitgandhi]

Thank you @raj-jain ; once Revision 1 is finalized I will release a new version of this package that reduces the FF3 tweakLen to 7 (bytes), and increase the feistelMin of both FF1 and FF3 implementations from 100 to 1000000