Random results in custom encryption / decryption function - php

Question

Im trying to encrypt data through a custom function i created... (based on base64)
The code works but to a degree... it gives random results (sometimes work and sometimes doesn't).
<?php
set_time_limit(0);
class encryptor{
function encrypt($data){
$all = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!?#,.&*()$; ";
$chars = str_split($all, 1); // Split $all to array of single characters
$text_chars = str_split($data, 1); // Split $data to array of single characters
// Create array of unique results based on the characters from $all
foreach($chars as $char){
$array[$char] = md5(uniqid(rand(), true));
}
// Replace the input text with the results from $array
foreach($text_chars as $text_char){
$data = str_replace($text_char,$array[$text_char], $data);
}
// Encode and compress $array as $solution
$solution = gzcompress(base64_encode(json_encode($array)),9);
// Return the encoded solution + Breaker + encoded and compressed input text
return $solution."BREAKHERE".gzcompress(base64_encode($data),9);
}
function decrypt($data){
// Break the encrypted code to two parts
$exploded = explode('BREAKHERE', $data);
// Decoding the contents
$contents = base64_decode(gzuncompress($exploded[1]));
// Decoding solution ($array)
$solves = json_decode(base64_decode(gzuncompress($exploded[0])),true);
$fliped = array_flip($solves);
// Replace the encrypted data with the solution
foreach($solves as $solve){
$contents = str_replace($solve,$fliped[$solve], $contents);
}
return($contents); // Return decoded data
}
}
$text = "11 1";
$enc = new encryptor();
$encrypted = $enc->encrypt($text);
$decrypted = $enc->decrypt($encrypted);
echo $decrypted;
?>

Answer 1

Since its just for fun, this change appears to make it work:
// Replace the input text with the results from $array
$encrypted = '';
foreach($text_chars as $text_char){
//$data = str_replace($text_char,$array[$text_char], $data);
$encrypted .= $array[$text_char];
}
Running str_replace in the loop results in substitutions of data that have been previously substituted.
Aside from that, to make transport of the encrypted data easier, I'd change:
return $solution."BREAKHERE".gzcompress(base64_encode($data),9);
to:
return base64_encode($solution."BREAKHERE".gzcompress($data,9);
and then make the appropriate changes in the decryptor. The compress data can have null characters and non-printable characters so if you base64 encode the entire result you can pass it around more easily.