From c29194ec465aaf3c5478c6b03ec70e4772518216 Mon Sep 17 00:00:00 2001
From: Francois Beutin <francois.beutin@ledger.fr>
Date: Tue, 17 Oct 2023 15:55:24 +0200
Subject: [PATCH] Review

---
 src/globals.h             | 6 +++++-
 src/process_transaction.c | 2 ++
 src/set_partner_key.c     | 2 +-
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/src/globals.h b/src/globals.h
index 2f6d1b27..7bf77b88 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -14,7 +14,7 @@
 #define MAX_DER_SIGNATURE_LENGTH 72U
 
 #define CURVE_SECP256K1 0x00
-#define CURVE_256R1     0x01
+#define CURVE_SECP256R1 0x01
 
 #define ENCODING_BYTES_ARRAY 0x00
 #define ENCODING_BASE_64_URL 0x01
@@ -86,6 +86,10 @@ typedef struct swap_app_context_s {
         };
     };
 
+    // During TX reception, we don't know if we'll receive the signature of the (TX), or the
+    // signature of the ('.' + TX).
+    // Storing the whole TX to calculate the hash during signature checking would use too much
+    // stack, so we calculate the two hashes and we'll decide later which one to use.
     uint8_t sha256_digest_prefixed[32];
     uint8_t sha256_digest_no_prefix[32];
 
diff --git a/src/process_transaction.c b/src/process_transaction.c
index 002d88e7..b01f6e74 100644
--- a/src/process_transaction.c
+++ b/src/process_transaction.c
@@ -103,6 +103,8 @@ static bool calculate_sha256_digest(buf_t payload) {
     cx_sha256_init(&sha256_prefix);
     cx_sha256_init(&sha256_no_prefix);
 
+    // Calculate both WITH and WITHOUT the dot prefix.
+    // We don't know which one we'll need yet
     unsigned char dot = '.';
     if (cx_hash_no_throw(&sha256_prefix.header, 0, &dot, 1, NULL, 0) != CX_OK) {
         PRINTF("Error: cx_hash_no_throw\n");
diff --git a/src/set_partner_key.c b/src/set_partner_key.c
index b96e3257..91cd6c90 100644
--- a/src/set_partner_key.c
+++ b/src/set_partner_key.c
@@ -46,7 +46,7 @@ static uint16_t parse_set_partner_key_command(const command_t *cmd,
         }
         if (curve_id == CURVE_SECP256K1) {
             *curve = CX_CURVE_SECP256K1;
-        } else if (curve_id == CURVE_256R1) {
+        } else if (curve_id == CURVE_SECP256R1) {
             *curve = CX_CURVE_256R1;
         } else {
             PRINTF("Error: Incorrect curve specifier %d\n", curve_id);