Added in 3.3

$hotp(key, count, hash, digits, encoding)

Returns an HOTP (HMAC-based One-Time Password) based on the specified parameters.

Parameters

key - The key to hash.
count - a unique number.
hash - Hash method to hash the key with. (sha1, sha256, sha384, sha512, md5, sha1 is default)
digits - Number of digits to return. (3 - 6, default is 6)
encoding - Sets encoding method. (-1 = auto, 0 = plain text, 1 = hex, 2 = base32)