I know about `random_bytes()` in PHP 7, and I want to use it for generating a cryptographically secure (e.g. hard to guess) random string for use as a one-time token or for longer term storage in a cookie.

Unfortunately, I don't know how to convert the output of `random_bytes()` to a string consisting only of human readable characters, so browsers don't get confused. I know about `bin2hex()`, but I'd prefer to use the full ASCII-range instead of hex numbers, for the sake of more bits per length.

Any ideas?