From c77f1114a65208be5c28e667ca4addc01471c72a Mon Sep 17 00:00:00 2001
From: Andrew Kozlik <andrew.kozlik@gmail.com>
Date: Mon, 7 Aug 2023 10:57:09 +0200
Subject: [PATCH] fixup! feat(core): Implement OPTIGA provisioning in prodtest.

---
 core/embed/prodtest/main.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/core/embed/prodtest/main.c b/core/embed/prodtest/main.c
index 156909923..23992b0bc 100644
--- a/core/embed/prodtest/main.c
+++ b/core/embed/prodtest/main.c
@@ -975,7 +975,10 @@ static void keyfido_write(char *data) {
 
   // Decrypt the FIDO attestation key.
   uint8_t fido_key[32] = {0};
-  uint8_t iv[16] = {0};
+
+  // The IV is intentionally all-zero, which is not a problem, because the
+  // encryption key is unique for each ciphertext.
+  uint8_t iv[AES_BLOCK_SIZE] = {0};
   aes_ret = aes_cbc_decrypt(&data_bytes[CIPHERTEXT_OFFSET], fido_key,
                             sizeof(fido_key), iv, &ctx);
   memzero(&ctx, sizeof(ctx));