Box.Sval secret_key : storage Fmt.tsecret_key formats a secret_key in this fashion: (Box.secret_key AAAAAA==). If the storage value is not Sodium.Box.secret_key_size bytes long, it will be formatted as (Box.secret_key <size mismatch>).
val public_key : storage Fmt.tpublic_key formats a public_key in this fashion: (Box.public_key AAAAAA==). If the storage value is not Sodium.Box.public_key_size bytes long, it will be formatted as (Box.public_key <size mismatch>).
val channel_key : storage Fmt.tchannel_key formats a channel_key in this fashion: (Box.channel_key AAAAAA==). If the storage value is not Sodium.Box.channel_key_size bytes long, it will be formatted as (Box.channel_key <size mismatch>).