US Patent 7881466 Method and system for obfuscating a cryptographic function

Embodiments include a system, wherein a server provides a cryptographic function F to an execution device in an obfuscated form. The function F composes output of a plurality of the mapping tables Ti (0≦i≦n; n≧1) using an Abelian group operator. A processor chooses tables O and C such that C[x] O[x]=0, x Di and creates tables T′i, 0≦i≦m; n≦m≦n+1, where for 0≦i≦n, each Table T′i represents the respective corresponding table Ti and at least one table T′o1, 0≦o1≦n, being formed through an Abelian composition of To1 and O, and at least one table T′c1, 0≦c1≦m, c1≠oj; being formed through an Abelian composition that includes C.