Cryptographic strategy implementing this standard may be enclosed by foreign patents and U.S. issued to the International Business Machines Corporation. Though, IBM has granted nonexclusive, royalty-free licenses under the patents to make, use and sell apparatus which complies with the usual. The terms, conditions and scope of the licenses are set out in notices published in the May 13, 1975 and August 31, 1976 issues of the Official Gazette of the United States Patent and Trademark Office (934 O.G. 452 and 949 O.G. 1717).