diff --git a/doc/Caliptra.md b/doc/Caliptra.md index 34dc38ac..36285eec 100644 --- a/doc/Caliptra.md +++ b/doc/Caliptra.md @@ -1246,7 +1246,7 @@ All fuse based cryptographic keying material and seeds (for example, UDS Seed) s SoC shall support in-field programmable fusing. [Fuse Map](#fuse-map) shows which fuses are expected to be in-field programmable. SoCs shall implement authorization for in-field programmable fusing to mitigate denial-of-service attacks. Authorization design is outside the scope of this specification. In Subsystem mode, SoC may use MCU RT FW for these actions. -SoC shall support a field entropy programming API. The API shall support retrieving an input value from an external interface. It should cryptographically mix that value with the output of an on-die TRNG to generate the field entropy value. The API implementation shall burn the field entropy value into the first available field entropy fuse slot (or fail if no slots are available). Caliptra is expected to be in any security state. The device owner is expected to call this API in a “clean room environment” to minimize risk of attack on the programming process. In Subsystem mode, SoC may use MCU RT FW for these actions. +SoC shall support a field entropy programming API. It should cryptographically generate a value from an on-die TRNG and used as the field entropy value. The API implementation shall burn the field entropy value into the first available field entropy fuse slot (or fail if no slots are available). Caliptra is expected to be in Caliptra Production state. The device owner is expected to call this API in a “clean room environment” to minimize risk of attack on the programming process. #### Fuse zeroing