1. A cryptographic processing unit for cryptographic processing in conjunction with a general purpose processor, the cryptographic processing unit comprising: a cryptographic processor, the cryptographic processor configured to: receive a script identifier from the general purpose processor; verify that a script identified by the script identifier is authorized for execution on the cryptographic processor; execute the script to produce a script result; and determine whether the script result comprises a critical security parameter that cannot be output from the cryptographic processor in unencrypted form; a protected memory that stores a secret key, wherein the cryptographic processor is further configured to encrypt at least the critical security parameter in the script result using the secret key, wherein the general purpose processor executes a set of instructions stored in a general non-transitory computer readable memory, wherein the cryptographic processing unit is configured to: access the general non-transitory computer readable memory to read the set of instructions; and verify, using at least one verification value stored in the protected memory, that the set of instructions has not been altered, wherein the general non-transitory computer readable memory is accessible via a general debugging interface, wherein the cryptographic processing unit further comprises a cryptographic processing unit debugging interface, wherein each of the general debugging interface and the cryptographic processing unit debugging interface is independently controlled, wherein the general debugging interface is controlled using a first electronic fuse block, and wherein the cryptographic processing unit comprises a second electronic fuse block for controlling the cryptographic processing unit debugging interface.