class Crypto::Bcrypt


Pure Crystal implementation of the Bcrypt algorithm by Niels Provos and David Mazières, as presented at USENIX in 1999.

The algorithm has a maximum password length limit of 71 characters (see this comment on stackoverflow).

Refer to Crypto::Bcrypt::Password for a higher level interface.

About the Cost

Bcrypt, like the PBKDF2 or scrypt ciphers, are designed to be slow, so generating rainbow tables or cracking passwords is nearly impossible. Yet, computers are always getting faster and faster, so the actual cost must be incremented every once in a while. Always use the maximum cost that is tolerable, performance wise, for your application. Be sure to test and select this based on your server, not your home computer.

This implementation of Bcrypt is currently 50% slower than pure C solutions, so keep this in mind when selecting your cost. It may be wise to test with Ruby's bcrypt gem which is a binding to OpenBSD's implementation.

Last but not least: beware of denial of services! Always protect your application using an external strategy (eg: rate limiting), otherwise endpoints that verifies bcrypt hashes will be an easy target.

Defined in:


Constant Summary

COST_RANGE = 4..31


Class Method Summary

Instance Method Summary

Instance methods inherited from class Reference

==(other : self)
==(other : JSON::Any)
==(other : YAML::Any)
, dup dup, hash(hasher) hash, inspect(io : IO) : Nil inspect, object_id : UInt64 object_id, pretty_print(pp) : Nil pretty_print, same?(other : Reference) : Bool
same?(other : Nil)
, to_s(io : IO) : Nil to_s

Constructor methods inherited from class Reference

new new

Instance methods inherited from class Object

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
, in?(collection : Object) : Bool
in?(*values : Object) : Bool
, inspect(io : IO) : Nil
inspect : String
, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil! not_nil!, pretty_inspect(width = 79, newline = "\n", indent = 0) : String pretty_inspect, pretty_print(pp : PrettyPrint) : Nil pretty_print, responds_to?(name : Symbol) : Bool responds_to?, tap(&) tap, to_json(io : IO) : Nil
to_json : String
, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil
, to_s(io : IO) : Nil
to_s : String
, to_yaml(io : IO) : Nil
to_yaml : String
, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

Class methods inherited from class Object

from_json(string_or_io, root : String)
, from_yaml(string_or_io : String | IO) from_yaml

Constructor Detail

def : String, salt : String, cost = DEFAULT_COST) #

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def : Bytes, salt : Bytes, cost = DEFAULT_COST) #

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Class Method Detail

def self.hash_secret(password, cost = DEFAULT_COST) : String #

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Instance Method Detail

def cost : Int32 #

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def digest : Bytes #

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def inspect(io : IO) : Nil #
Description copied from class Reference

Appends a String representation of this object which includes its class name, its object address and the values of all instance variables.

class Person
  def initialize(@name : String, @age : Int32)
end"John", 32).inspect # => #<Person:0x10fd31f20 @name="John", @age=32>

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def password : Bytes #

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def salt : Bytes #

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def to_s(io : IO) : Nil #
Description copied from class Reference

Appends a short String representation of this object which includes its class name and its object address.

class Person
  def initialize(@name : String, @age : Int32)
end"John", 32).to_s # => #<Person:0x10a199f20>

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def to_s : String #
Description copied from class Object

Returns a string representation of this object.

Descendants must usually not override this method. Instead, they must override #to_s(io), which must append to the given IO object.

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def to_slice(*args, **options) #

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def to_slice(*args, **options, &) #

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