Answer:
Security Innovation NTRU cryptographic software invention and reference source code for NTRUEncrypt are released to public domain under CCO 1.0 license.
Invention U.S. Patent No. U.S. Issue Date U.S. Application No. U.S. Filing Date Countries
Public key cryptosystem method and apparatus 6,081,597 Jun 27, 2000 08/914,449 Aug 19, 1997 US, Japan, Canada, Australia, Israel, China, Europe
Ring-based public key cryptosystem method 6,298,137 Oct 2, 2001 09/543,708 Apr 5, 2000 US, Europe, Canada
Speed enhanced cryptographic method and apparatus 7,031,468 Apr 18, 2006 09/939,531 Aug 24, 2001 US, Europe, Canada
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