to_s

        # OpenSSL::HMAC.to_s

(from ruby core)
### Implementation from HMAC
---
    to_s()

---

Returns the authentication code as a hex-encoded string. The *digest*
parameter specifies the digest algorithm to use. This may be a String
representing the algorithm name or an instance of OpenSSL::Digest.

### Example
    key = 'key'
    data = 'The quick brown fox jumps over the lazy dog'

    hmac = OpenSSL::HMAC.hexdigest('SHA1', key, data)
    #=> "de7c9b85b8b78aa6bc8a7a36f70a90701c9db4d9"


(This method is an alias for OpenSSL::HMAC#hexdigest.)

Returns the authentication code an instance represents as a hex-encoded
string.