The storage and retrieval of cryptographic key materials from a storage database utilizes a limited one-way function to create computational barriers. The limited one-way function is asymmetric in nature, in terms of work to compute and work to invert, to store and retrieve encryption keys. The limited one-way function is not intractable, but alternatively, there is some measurable difference in the amount of work required to invert a stored encryption key, compared to the work required for a calculation of the output of the one-way function for storage of an encryption key in a database.