| 摘要 |
The present invention provides a solution to the problem of guaranteeing the integrity of software programmes by encrypting all or part of each instruction of a programme using a key based on all or part of one or a plurality of previous instructions, thus resulting in a different encryption key per instruction. The invention is applicable to software programmes whose structures are not necessarily tree-like in nature and is also applicable when the programme includes loops, jumps, calls or breaks etc. The invention allows for an exception to be flagged when an encrypted instruction is wrongly decrypted. There is no need for the first instruction to be in clear, since the instruction key may be appropriately initialised as required. The invention can be realised in software or entirely in hardware thereby eliminating the possibility of a third party intercepting a decrypted instruction or a decryption key. |
