Split A String at X, then at Y Value - php

Question

I have the following code:
$Field = $FW->Encrypt("Test");
echo "<pre>";
print_r($Field);
echo "</pre>";
# $IV_Count = strlen($Field['IV']);
# $Key_Count = strlen($Field['Key']);
# $Cipher_Count = strlen($Field['CipheredText']);
foreach ($Field AS $Keys => $Values){
echo $Keys."Count = ".strlen($Values)."<br><br>";
}
The output is as:
Array
(
[CipheredText] => x2nelnArnS1e2MTjOrq+wd9BxT6Ouxksz67yVdynKGI=
[IV] => 16
[Key] => III#TcTf‡eB12T
)
CipheredTextCount = 44
IVCount = 2
KeyCount = 16
The IV/KeyCount is always returning the same value regardless of the input. But the CipheredTextCount changes depending on the input.. For example:
$Field = $FW->Encrypt("This is a longer string");
The foreach loop returns:
CipheredTextCount = 64
IVCount = 2
KeyCount = 16
and now for my question. Lets take the first example with the TextCount of 44
How can I split a string after implode("",$Field); to display as the original array? an example would be:
echo implode("",$Field);
Which outputs:
ijGglH/vysf52J5aoTaDVHy4oavEBK4mZTrAL3lZMTI=16III#TcTf‡eB12T
Based on the results from the strlen?
It is possible to store the count of the first $Cipher_Count in a database for a reference
My current setup involves storing the key and IV in a seperate column away from the ciphered text string.. I need this contained within one field and the script handles the required information to do the following:
Retrieve The long string > Split string to the original array > Push
array to another function > decrypt > return decoded string.

Answer 1

Why not use serialize instead? Then when you get the data out of the database, you can use unserialize to restore it to an array.

Answer 2

$Combined_Field = implode("",$Field);
echo $str1 = substr($Combined_Field, 0, $Cipher_Count)."<br><br>";
echo $str2 = substr($Combined_Field,$Cipher_Count,$IV_Count)."<br><br>";
echo $str3 = substr($Combined_Field, $IV_Count+$Cipher_Count,$Key_Count);
Or use a function:
function Cipher_Split($Cipher, $Cipher_Count, $KeyCount, $IVCount){
return array(
"Ciphered Text" => substr($Cipher,0,$Cipher_Count),
"IV" => substr($Cipher,$Cipher_Count,$IVCount),
"Key" => substr($Cipher,$IVCount+$Cipher_Count,$KeyCount)
);
}