Device and method for updating code

A computer-implemented method of a software provider (25) enabling a software-acquiring entity (20) to arrive from an existent first signed piece of code (11), which is executable on a machine, at a second signed piece of code (12, 13), which is executable on the machine, both pieces of code (11, 12, 13) having been generated by use of a first software archive generator (2) under use of generation instructions (8), comprising the step of:

• providing to said software-acquiring entity (20) a difference code (4, 5), said difference code comprising the steps necessary to arrive from said first signed piece of code (11) at said second signed piece of code (12, 13), said steps further including instructions to amend said first signed piece of code so that a signature belonging to said second signed piece of code is the same signature for a corresponding second signed piece of code existing at the software provider, said difference code (4, 5) is usable at said software-acquiring entity (20);
• and
• amending using said difference code said first signed piece of code (11) by a second software archive generator (7) to generate said second signed piece of code (12, 13), whereby said second software archive generator (7) is fed with those generation instructions (8) that were used by said first software archive generator (2) for the generation of both pieces of code (11, 12, 13),
• wherein for more than two nieces of code (11, 12, 13) being stored, the difference code (4, 5) is generated only between a subset of said pieces of code (11, 12, 13) and wherein for arriving from the first piece of code (11) to the second piece of code (13) several difference codes (4, 5) are required, these difference codes (4, 5) are merged to a single difference code to be provided to the software-acquiring entity (20).