US Patent 10511436 Protecting key material using white-box cryptography and split key techniques

Key material is protected using white-box cryptography and split key techniques. An exemplary method comprises splitting a secret key of a software application provider into a plurality of key shares, wherein a subset of the plurality of key shares is needed to reconstruct the secret key; using one key share to encrypt the remaining key shares to obtain a set of wrapped key shares; applying the one key share to a white-box cryptography compiler to generate a white-box cryptographic program; generating a user application linked to the white-box cryptography program; distributing the user application to a user; and providing one wrapped key share to a relying party, wherein, the relying party provides a challenge and the one wrapped key share of the relying party to the user application, wherein the user application provides the one wrapped key share of the relying party to the white-box cryptographic program and obtains a digital signature for the relying party, and wherein the relying party verifies the signature.