Abstract: 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.

Abstract: In a system 300, a server 310 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 312 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 T,j and at least one table T?o1, 0?01, ?n, being formed through an Abelian composition of To1 and O, and at least one table T?c10?c1,?m, c1#oj, being formed through an Abelian composition that includes C. Means 314 are used for providing the tables T?i, to the executing device. The executing device 320 includes means 324 for receiving the tables and a processor 322 for forming a function F? that is functionally equivalent to the cryptographic function F by an Abelian composition of the tables T?i.

Abstract: A method for implementing a recycle bin function for a first electronic device comprising data storage for storing electronic files. The method comprises receiving an indication to delete a file stored on the first electronic device, determining a further electronic device also storing the file, storing on the first electronic device a reference to the further electronic device and the file, and releasing the data storage capacity occupied by the file on the first electronic device so that the capacity is available for other uses.