Dns.SshfpSourceSecure shell fingerprint
The secure shell (SSH) applies trust on first use, and can store fingerprints as SSHFP records in DNS, which is then used as a second channel.
algorithm_to_int a is the 8 bit integer representation of algorithm a.
int_to_algorithm i decodes i to the algorithm constructor.
The type of a SSH fingerprint record, consisting of algorithm, typ, and actual fingerprint.