Detect base64 encoding in PHP?

Question

Is there some way to detect if a string has been base64_encoded() in PHP?

We\'re converting some storage from plain text to base64 and part of it lives in a cookie

Answer 1

Usually a text in base64 has no spaces.

I used this function which worked fine for me. It tests if the number of spaces in the string is less than 1 in 20.

e.g: at least 1 space for each 20 chars --- ( spaces / strlen ) < 0.05

function normalizaBase64($data){
    $spaces = substr_count ( $data ," ");
    if (($spaces/strlen($data))<0.05)
    {
        return base64_decode($data);
    }
    return $data;
}