1. A method comprising: storing a public key of a first private-public key pair in at least one data memory associated with a cryptographic processing system comprising a hardware processor; receiving, by the cryptographic processing system, a public key of a second private-public key pair signed with a private key of the first private-public key pair; verifying, by the cryptographic processing system, the signed public key using the public key of the first private-public key pair; storing the public key of the second private-public key pair in the at least one data memory; receiving, by the cryptographic processing system, secure code signed with a private key of the second private-public key pair; verifying, by the cryptographic processing system, the signed secure code using the public key of the second private-public key pair; and storing the secure code in the at least one data memory, the secure code including one or more functions and a new function table that identifies a location of one or more of the functions; wherein one or more original functions are stored in a first data memory located internal to the cryptographic processing system, and wherein the storing the secure code in the at least one data memory comprises storing, by the cryptographic processing system, in a second data memory located external to the cryptographic processing system, the secure code including one or more new or updated functions and the new function table, the new function table identifying a location of the one or more of the original functions stored in the first data memory and a location of the one or more of the new or updated functions stored in the second data memory.