diff --git a/composer.json b/composer.json
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,8 @@
         "global functions"
     ],
     "require": {
-        "php": ">=5.4.0"
+        "php": ">=7.1.0",
+        "keruald/omnitools": "dev-master"
     },
     "require-dev": {
         "phpunit/phpunit": "^7"
diff --git a/core.php b/core.php
--- a/core.php
+++ b/core.php
@@ -2,6 +2,8 @@
 
 namespace Keruald;
 
+use Keruald\OmniTools\Strings\Multibyte\StringUtilities;
+
 /**
  * Keruald, core libraries for Pluton and Xen engines.
  *
@@ -22,40 +24,10 @@
  * @param string $encoding the character encoding (optional)
  *
  * @return string the padded string
- *
+ * @deprecated Use Keruald\OmniTools\Strings\Multibyte\StringUtilities::pad
  */
 function mb_str_pad($input, $pad_length, $pad_string = ' ', $pad_type = STR_PAD_RIGHT, $encoding = null) {
-    // Inspired by Ronald Ulysses Swanson method
-    // http://stackoverflow.com/a/27194169/1930997
-    // who followed the str_pad PHP implementation.
-
-    if ($encoding === null) {
-        $encoding = mb_internal_encoding();
-    }
-
-    $padBefore = $pad_type === STR_PAD_BOTH || $pad_type === STR_PAD_LEFT;
-    $padAfter = $pad_type === STR_PAD_BOTH || $pad_type === STR_PAD_RIGHT;
-
-    $pad_length -= mb_strlen($input, $encoding);
-    if ($padBefore && $padAfter) {
-        $targetLength = $pad_length / 2;
-    } else {
-        $targetLength = $pad_length;
-    }
-    $strToRepeatLength = mb_strlen($pad_string, $encoding);
-    $repeatTimes = ceil($targetLength / $strToRepeatLength);
-    $repeatedString = str_repeat($pad_string, max(0, $repeatTimes)); // safe if used with valid Unicode sequences (any charset)
-
-    $paddedString = '';
-    if ($padBefore) {
-        $paddedString = mb_substr($repeatedString, 0, floor($targetLength), $encoding);
-    }
-    $paddedString .= $input;
-    if ($padAfter) {
-        $paddedString .= mb_substr($repeatedString, 0, ceil($targetLength), $encoding);
-    }
-
-    return $paddedString;
+    return StringUtilities::pad($input, $pad_length, $pad_string, $pad_type, $encoding);
 }
 
 /**