From b03a651499f2f8f98860d0fedfbe93e2cceb190b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Sun, 14 Sep 2025 10:48:26 -0500
Subject: [PATCH] [md5] Optimize MD5::get_hex() to eliminate sprintf dependency

---
 esphome/components/md5/md5.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/esphome/components/md5/md5.cpp b/esphome/components/md5/md5.cpp
index 980cb98699..fb0d9f401f 100644
--- a/esphome/components/md5/md5.cpp
+++ b/esphome/components/md5/md5.cpp
@@ -1,4 +1,3 @@
-#include <cstdio>
 #include <cstring>
 #include "md5.h"
 #ifdef USE_MD5
@@ -44,7 +43,11 @@ void MD5Digest::get_bytes(uint8_t *output) { memcpy(output, this->digest_, 16);
 
 void MD5Digest::get_hex(char *output) {
   for (size_t i = 0; i < 16; i++) {
-    sprintf(output + i * 2, "%02x", this->digest_[i]);
+    uint8_t byte = this->digest_[i];
+    uint8_t high = byte >> 4;
+    uint8_t low = byte & 0x0F;
+    output[i * 2] = high < 10 ? '0' + high : 'a' + (high - 10);
+    output[i * 2 + 1] = low < 10 ? '0' + low : 'a' + (low - 10);
   }
 }