sig
exception Invalid_count of int
exception Invalid_seed of string
exception Urandom_error of exn
exception Gensalt_error
exception Bcrypt_error
type hash_t
val hash : ?count:int -> ?seed:string -> string -> Bcrypt.hash_t
val verify : string -> Bcrypt.hash_t -> bool
external hash_of_string : string -> Bcrypt.hash_t = "%identity"
external string_of_hash : Bcrypt.hash_t -> string = "%identity"
end