Translating algorithm/code from Ruby to PHP

Question

digest = HMAC.digest(Digest.new(SHA1), Base64.decode64(key), HashString) return Base64.encode64(digest.to_s()).chomp()

What would the above be in PHP?

Answer 1

This should do it:

$digest = hash_hmac("sha1", $hash_string, base64_decode($key), true);
return base64_encode($digest);