<?php
/* Коды для замены букв */
'ц' => '1',
'О' => '2',
'в' => '3',
'у' => '4',
'П' => '5',
'е' => '6',
'м' => '7',
'х' => '8',
'з' => '9',
'С' => '0',
'й' => '#'
);
$text = '25 - 84#';
$cipher = strtr($text, $decode);
echo "Оригинал: {$cipher}";
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