diff --git a/nugget/proto/nugget/app/keymaster/keymaster.proto b/nugget/proto/nugget/app/keymaster/keymaster.proto
index c85af6e..bcc3008 100644
--- a/nugget/proto/nugget/app/keymaster/keymaster.proto
+++ b/nugget/proto/nugget/app/keymaster/keymaster.proto
@@ -264,7 +264,7 @@
 // SetRootOfTrustRequest
 // Only callable by the Bootloader.
 message SetRootOfTrustRequest {
-  bytes digest = 1;
+  bytes digest = 1;                  // This is a SHA256 digest.
 }
 message SetRootOfTrustResponse {
   // Specified in keymaster_defs.proto:ErrorCode
@@ -275,7 +275,7 @@
 // Only callable by the Bootloader.
 message SetBootStateRequest {
   bool is_unlocked = 1;
-  bytes public_key = 2;
+  bytes public_key = 2;              // This is a SHA256 digest.
   uint32 color = 3;
   uint32 system_version = 4;
   uint32 system_security_level = 5;