A system and method of dynamically altering the encoding, structure or other attribute of a cryptographic key, typically a license activation key, to render useless keys that have been created by illegal key generation “cracks”. An encoding/decoding engine provides a plurality of key obfuscation algorithms that may alter the structure, encoding or any other attribute of a given key. A changeable combination code is supplied to the encoding/decoding engine that specifies a subset of the algorithms to apply during the encoding or decoding phase. The encoding engine is used during key generation and the decoding engine used during key usage. The same combination code must be used during decoding as was used during encoding to recover the original key or a valid key will not be recovered. Thus, a system can be rapidly re-keyed by selecting a new combination of encoding/decoding algorithms. The selection of algorithms comprises a combination code. The new combination code will result in keys that are incompatible with any existing illegal key generators.