# class OpenSSL::Cipher

- OpenSSL::Cipher
- Reference
- Object

##
Overview

A class which can be used to encrypt and decrypt data using a specified cipher.

NOTE The ciphers available to an application are determined by the linked version of the system SSL library. A comprehensive list of ciphers can be found in the OpenSSL Cipher documentation.

    require "random/secure"
    require "openssl"

    def encrypt(data, key, iv)
      cipher = OpenSSL::Cipher.new("aes-256-cbc")
      cipher.encrypt
      cipher.key = key
      cipher.iv = iv

      io = IO::Memory.new
      io.write(cipher.update(data))
      io.write(cipher.final)
      io.rewind

      io.to_slice
    end

    def decrypt(data, key, iv)
      cipher = OpenSSL::Cipher.new("aes-256-cbc")
      cipher.decrypt
      cipher.key = key
      cipher.iv = iv

      io = IO::Memory.new
      io.write(cipher.update(data))
      io.write(cipher.final)
      io.rewind

      io.gets_to_end
    end

    key = Random::Secure.random_bytes(64) # You can also use OpenSSL::Cipher#random_key to do this same thing
    iv = Random::Secure.random_bytes(32)  # You can also use OpenSSL::Cipher#random_iv to do this same thing

    encrypted_data = encrypt("Encrypted", key, iv)    # => Bytes[95, 182, 21, 86, 193, 155, 149, 164, 82, 102, 171, 182, 56, 153, 223, 33]
    decrypted_data = decrypt(encrypted_data, key, iv) # => "Encrypted"

##
Defined in:

openssl/cipher.cr

##
Constructors

- .new(name)

##
Instance Method Summary

- #authenticated? : Bool
- #block_size : Int32
- #decrypt : Nil

  Sets this cipher to decryption mode.

- #encrypt : Nil

  Sets this cipher to encryption mode.

- #final : Bytes

  Outputs the decrypted or encrypted buffer.

- #finalize
- #iv=(iv)
- #iv_len : Int32

  How many bytes the iv should be.

- #key=(key)
- #key_len : Int32

  How many bytes the key should be.

- #name : String
- #padding=(pad : Bool)
- #random_iv

  Sets the iv using `Random::Secure`.

- #random_key

  Sets the key using `Random::Secure`.

- #reset

  Resets the encrypt/decrypt mode.

- #update(data)

  Add the data to be encrypted or decrypted to this cipher's buffer.

### Instance methods inherited from class `Reference`

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

### Constructor methods inherited from class `Reference`

new new, unsafe_construct(address : Pointer, *args, **opts) : self unsafe_construct

### Class methods inherited from class `Reference`

pre_initialize(address : Pointer) pre_initialize

### Instance methods inherited from class `Object`

! : Bool !, !=(other) !=, !~(other) !~, ==(other) ==, ===(other : JSON::Any)
===(other : YAML::Any)
===(other) ===, =~(other) =~, as(type : Class) as, as?(type : Class) as?, class class, dup dup, hash(hasher)
hash hash, in?(collection : Object) : Bool
in?(*values : Object) : Bool in?, inspect(io : IO) : Nil
inspect : String inspect, is_a?(type : Class) : Bool is_a?, itself itself, nil? : Bool nil?, not_nil!(message)
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_json, to_pretty_json(indent : String = " ") : String
to_pretty_json(io : IO, indent : String = " ") : Nil to_pretty_json, to_s(io : IO) : Nil
to_s : String to_s, to_yaml(io : IO) : Nil
to_yaml : String to_yaml, try(&) try, unsafe_as(type : T.class) forall T unsafe_as

### Class methods inherited from class `Object`

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

### Macros inherited from class `Object`

class_getter(*names, &block) class_getter, class_getter!(*names) class_getter!, class_getter?(*names, &block) class_getter?, class_property(*names, &block) class_property, class_property!(*names) class_property!, class_property?(*names, &block) class_property?, class_setter(*names) class_setter, def_clone def_clone, def_equals(*fields) def_equals, def_equals_and_hash(*fields) def_equals_and_hash, def_hash(*fields) def_hash, delegate(*methods, to object) delegate, forward_missing_to(delegate) forward_missing_to, getter(*names, &block) getter, getter!(*names) getter!, getter?(*names, &block) getter?, property(*names, &block) property, property!(*names) property!, property?(*names, &block) property?, setter(*names) setter

##
Constructor Detail

def self.new(name) #

##
Instance Method Detail

def authenticated? : Bool #
def block_size : Int32 #
def decrypt : Nil #

Sets this cipher to decryption mode.

def encrypt : Nil #

Sets this cipher to encryption mode.

def final : Bytes #

Outputs the decrypted or encrypted buffer.

def finalize #
def iv=(iv) #
def iv_len : Int32 #

How many bytes the iv should be.

def key=(key) #
def key_len : Int32 #

How many bytes the key should be.

def name : String #
def padding=(pad : Bool) #
def random_iv #

Sets the iv using `Random::Secure`.

def random_key #

Sets the key using `Random::Secure`.

def reset #

Resets the encrypt/decrypt mode.

def update(data) #

Add the data to be encrypted or decrypted to this cipher's buffer.