title: convert base64 to base62 (without special characters)
body: <p>I want to pass a blowfish encrypted string in a URL, and want to encode it like base64, but without any special character, something like base62 would be great (0-9a-zA-Z). So what I'm trying to do is converting the blowfish encrypted string using base64_encode, and convert base64 to base62. </p>
  
  <p>I know about solutions how to make base64 url-safe, but I really don't want any special character in the string. convert_base() only works with base up to 36, the math extensions can convert up to base 62.</p>
  
  <p><strong>Has anybody a nice idea how to convert a base64 string to base62 using PHP?</strong></p>