Search and replace words (using random characters) contained in a text, using blacklists

Search and replace words with blacklist

<?php

  //  Text to filter and to censure
  $text_to_check = "Lorem ipsum DOLOR Bullshit";

  //  List of words to censor
  $blacklist_words = array("God", "em", "shit", "pig");
  //$blacklist_words = "shit";

  //  Function used to generate a random string length as word to replace
  function generateString($length) {

    $alph_char = array('33', '35', '36', '37', '38', '64');
    $resString = '';

    for ($i = 0; $i < $length; $i++)
        $resString .= chr($alph_char[array_rand($alph_char, 1)]);

    return $resString;

  }

  //  Function to analyze text and cancel words length shorter than 3 (three) characters
  function analyzePhrase($phrase) {

    for ($plo = 0; $plo <= count($phrase); $plo++) {

      if (strlen($phrase[$plo]) <= 3) {

        if (!is_numeric($phrase[$plo]))
          unset($phrase[$plo]);

      }

    }

    return count($phrase);

  }

  function censorshipWords($text_w, $censored) {

    $in_phrase = $text_w;

    if (isset($censored) && !empty($censored)){

      if (is_array($censored)) {

        for ($t = 0; $t < count($censored); $t++)
          $in_phrase = str_ireplace($censored[$t], generateString(strlen($censored[$t])), $in_phrase);

      } else {

        $in_phrase = str_ireplace($censored, generateString(strlen($censored)), $text_w);

      }

    } else {

      $in_phrase = $text_w;

    }

    return $in_phrase;

  }

  $the_phrase = explode(" ", htmlentities($text_to_check));
  $rm_filter = analyzePhrase($the_phrase);

  if (!empty($rm_filter))
    echo censorshipWords($text_to_check, $blacklist_words);