1. A computer-implemented method of accessing cryptographically protected information comprising, on a server system: receiving a request from a client system, the request including a cryptographic object; processing the request by: identifying, at the server system, cryptographically protected information associated with the cryptographic object; accessing the cryptographically protected information using the cryptographic object; sending, to the client system, data based at least in part on the cryptographically protected information; and in conjunction with completing processing of the request, irreversibly modifying the cryptographic object on the server system; wherein irreversibly modifying the cryptographic object on the server system comprises truncating the cryptographic object on the server system to generate a truncated cryptographic object.