Patent ID: 9385872
Filing Date: 2016-07-05
CPC Classification: H04L

Claim Text:
1. A method for effecting reissue, by a credential issuer of a data processing system, of a cryptographic credential certifying a set of attributes, the credential being initially bound to a first secret key stored in a first tamper-resistant processing device, the method comprising: producing a backup token using the first tamper-resistant processing device, the backup token comprising a commitment to said set of attributes and first proof data permitting verification that the set of attributes in said commitment corresponds to the set of attributes certified by said credential; storing the backup token in backup memory; at a second tamper-resistant processing device storing a second secret key, blinding the second secret key to produce a blinded key; producing a credential template token comprising the backup token and the blinded key; sending the credential template token to the credential issuer via user apparatus of the data processing system; and at the credential issuer, performing said verification using the first proof data and using the credential template token to provide a reissued credential, certifying said set of attributes, to the second tamper-resistant device via said user apparatus, the reissued credential being bound to the second secret key.