PRIORITY CLAIM

The present application is a National Phase entry of PCT Application No. PCT/EP2019/061236, filed May 2, 2019, which claims priority from EP Patent Application No. 18174202.4, filed May 24, 2018, each of which is hereby fully incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to improvements to the generation of cryptographic keys.

BACKGROUND

Hardware Security Modules (HSMs) are network-connected physical devices tasked with the secure generation, storage and provision of cryptographic keys for use by consuming resources such as computer systems, appliances, devices, software and users. For example, HSMs generate, store and provide public/private key pairs. HSMs employ deterministic random number generators to generate pseudo-random numbers for cryptographic key generation. An increasing use of technologies such as internet-of-things communications, distributed data structures for trusted storage of data and transactions (e.g. blockchains) and intercommunicating virtualized computer systems requires the generation of increasingly large volumes of cryptographic keys. The challenge is especially acute in view of the sheer volume of single use keys being requested of HSMs and being used and disposed over relatively short periods.

The use of pseudo-random numbers as a basis for key generation is widely acknowledged to be vulnerable due to their deterministic nature. Thus, the key generation facilities of such HSMs are not suitable for high-volume key generation. HSMs are also subject to strict compliance requirements. These compliance requirements can include, for example: the Common Criteria for Information Technology Security Evaluation (abbreviated as Common Criteria or CC) (international standard ISO/IEC 15408) for computer security certification; and Federal Information Processing Standard (FIPS) Publication 140-2, (FIPS PUB 140-2), a U.S. government computer security standard used to approve cryptographic modules. The need for such compliance leads to constraints on HSM capabilities such as rates of undertaking cryptography operations including key generation. Furthermore, the very nature of HSMs as secure and compliant components protected from interference and tampering renders them unsuitable or impossible for modification such as upgrading to increase processor, memory or other resources.

Thus, there is a challenge in providing requisite cryptographic operations to satisfy the growing demands of modern technology while retaining the necessary security compliance provided by HSMs.

SUMMARY

The present disclosure accordingly provides, in a first aspect, a computer implemented method of generating cryptographic keys for a plurality of hardware security modules (HSMs), the method comprising: generating a plurality of cryptographic keys for use by the HSMs in providing cryptography functions, wherein the cryptographic keys are generated based on numerical data generated by a hardware random number generator; and storing the generated cryptographic keys in a secure key store, such that a key in the key store utilized by an HSM is flagged as utilized to prevent other HSMs utilizing the same key, so as to provide a rate of generation and storage of the cryptographic keys unconstrained by the resources of any HSM.

In some embodiments a key in the key store is utilized by a consuming HSM by storing the key in the consuming HSM, the storage being achieved by invoking a storage function of the HSM, and the key is flagged as utilized when the key is so stored in the consuming HSM.

In some embodiments storage of the cryptographic keys in the consuming HSM is scheduled to occur at times when the HSM is operating in a low utilization state relative to an average utilization state of the HSM.

In some embodiments the hardware random number generator operates based on a statistically random entropy data source originating from natural phenomena.

In some embodiments the natural phenomena include one or more of: one or more statistically random noise signals; and quantum phenomena such as photoelectric effects.

The present disclosure accordingly provides, in a second aspect, a computer system including a processor and memory storing computer program code for performing the method set out above.

The present disclosure accordingly provides, in a third aspect, a computer program element comprising computer program code to, when loaded into a computer system and executed thereon, cause the computer to perform the method set out above.

