Secure debug architecture

A method comprising:

• receiving a request from a host device for access to an integrated circuit via a debug interface of the integrated circuit;
• responsive to the request, generating a random number using the integrated circuit;
• transmitting the random number from the integrated circuit to the host device via the debug interface;
• receiving, from the host device via the debug interface, input data that has been encrypted using the random number as a key, wherein the input data includes at least one of a debug command and a firmware image;
• decrypting the input data, within the integrated circuit, using the random number as a key;
• and
• update content of an authenticated register in an authentication circuit based on comparison of the input data to a value stored in non-volatile memory of the integrated circuit, wherein the authentication circuit is configured to update content of an authorization register in the debug interface based on the content of the authenticated register.

A method comprising:

• transmitting a request from a host device for access to an integrated circuit via a debug interface of the integrated circuit;
• receiving, using the host device, a random number from the integrated circuit via the debug interface;
• encrypting, on the host device, input data using the random number as a key, wherein the input data includes at least one of a debug command and a firmware image;
• signing data using a signing key to obtain signed data, in which the input data includes the signed data;
• and
• transmitting from the host device to the integrated circuit via the debug interface the encrypted input data.