godot-docs/classes/class_crypto.rst

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.. _class_Crypto:

Crypto
======

**Inherits:** :ref:`RefCounted<class_RefCounted>` **<** :ref:`Object<class_Object>`

Provides access to advanced cryptographic functionalities.

.. rst-class:: classref-introduction-group

Description
-----------

The Crypto class provides access to advanced cryptographic functionalities.

Currently, this includes asymmetric key encryption/decryption, signing/verification, and generating cryptographically secure random bytes, RSA keys, HMAC digests, and self-signed :ref:`X509Certificate<class_X509Certificate>`\ s.


.. tabs::

 .. code-tab:: gdscript

    extends Node
    
    var crypto = Crypto.new()
    var key = CryptoKey.new()
    var cert = X509Certificate.new()
    
    func _ready():
        # Generate new RSA key.
        key = crypto.generate_rsa(4096)
        # Generate new self-signed certificate with the given key.
        cert = crypto.generate_self_signed_certificate(key, "CN=mydomain.com,O=My Game Company,C=IT")
        # Save key and certificate in the user folder.
        key.save("user://generated.key")
        cert.save("user://generated.crt")
        # Encryption
        var data = "Some data"
        var encrypted = crypto.encrypt(key, data.to_utf8_buffer())
        # Decryption
        var decrypted = crypto.decrypt(key, encrypted)
        # Signing
        var signature = crypto.sign(HashingContext.HASH_SHA256, data.sha256_buffer(), key)
        # Verifying
        var verified = crypto.verify(HashingContext.HASH_SHA256, data.sha256_buffer(), signature, key)
        # Checks
        assert(verified)
        assert(data.to_utf8_buffer() == decrypted)

 .. code-tab:: csharp

    using Godot;
    using System.Diagnostics;
    
    public partial class MyNode : Node
    {
        private Crypto _crypto = new Crypto();
        private CryptoKey _key = new CryptoKey();
        private X509Certificate _cert = new X509Certificate();
    
        public override void _Ready()
        {
            // Generate new RSA key.
            _key = _crypto.GenerateRsa(4096);
            // Generate new self-signed certificate with the given key.
            _cert = _crypto.GenerateSelfSignedCertificate(_key, "CN=mydomain.com,O=My Game Company,C=IT");
            // Save key and certificate in the user folder.
            _key.Save("user://generated.key");
            _cert.Save("user://generated.crt");
            // Encryption
            string data = "Some data";
            byte[] encrypted = _crypto.Encrypt(_key, data.ToUtf8Buffer());
            // Decryption
            byte[] decrypted = _crypto.Decrypt(_key, encrypted);
            // Signing
            byte[] signature = _crypto.Sign(HashingContext.HashType.Sha256, Data.Sha256Buffer(), _key);
            // Verifying
            bool verified = _crypto.Verify(HashingContext.HashType.Sha256, Data.Sha256Buffer(), signature, _key);
            // Checks
            Debug.Assert(verified);
            Debug.Assert(data.ToUtf8Buffer() == decrypted);
        }
    }



.. rst-class:: classref-reftable-group

Methods
-------

.. table::
   :widths: auto

   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`bool<class_bool>`                       | :ref:`constant_time_compare<class_Crypto_method_constant_time_compare>` **(** :ref:`PackedByteArray<class_PackedByteArray>` trusted, :ref:`PackedByteArray<class_PackedByteArray>` received **)**                                                                                                                                             |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`decrypt<class_Crypto_method_decrypt>` **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PackedByteArray<class_PackedByteArray>` ciphertext **)**                                                                                                                                                                                       |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`encrypt<class_Crypto_method_encrypt>` **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PackedByteArray<class_PackedByteArray>` plaintext **)**                                                                                                                                                                                        |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`generate_random_bytes<class_Crypto_method_generate_random_bytes>` **(** :ref:`int<class_int>` size **)**                                                                                                                                                                                                                                |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`CryptoKey<class_CryptoKey>`             | :ref:`generate_rsa<class_Crypto_method_generate_rsa>` **(** :ref:`int<class_int>` size **)**                                                                                                                                                                                                                                                  |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`X509Certificate<class_X509Certificate>` | :ref:`generate_self_signed_certificate<class_Crypto_method_generate_self_signed_certificate>` **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`String<class_String>` issuer_name="CN=myserver,O=myorganisation,C=IT", :ref:`String<class_String>` not_before="20140101000000", :ref:`String<class_String>` not_after="20340101000000" **)** |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`hmac_digest<class_Crypto_method_hmac_digest>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` key, :ref:`PackedByteArray<class_PackedByteArray>` msg **)**                                                                                                                 |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`PackedByteArray<class_PackedByteArray>` | :ref:`sign<class_Crypto_method_sign>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` hash, :ref:`CryptoKey<class_CryptoKey>` key **)**                                                                                                                                          |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
   | :ref:`bool<class_bool>`                       | :ref:`verify<class_Crypto_method_verify>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` hash, :ref:`PackedByteArray<class_PackedByteArray>` signature, :ref:`CryptoKey<class_CryptoKey>` key **)**                                                                             |
   +-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

.. rst-class:: classref-section-separator

----

.. rst-class:: classref-descriptions-group

Method Descriptions
-------------------

.. _class_Crypto_method_constant_time_compare:

.. rst-class:: classref-method

:ref:`bool<class_bool>` **constant_time_compare** **(** :ref:`PackedByteArray<class_PackedByteArray>` trusted, :ref:`PackedByteArray<class_PackedByteArray>` received **)**

Compares two :ref:`PackedByteArray<class_PackedByteArray>`\ s for equality without leaking timing information in order to prevent timing attacks.

See `this blog post <https://paragonie.com/blog/2015/11/preventing-timing-attacks-on-string-comparison-with-double-hmac-strategy>`__ for more information.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_decrypt:

.. rst-class:: classref-method

:ref:`PackedByteArray<class_PackedByteArray>` **decrypt** **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PackedByteArray<class_PackedByteArray>` ciphertext **)**

Decrypt the given ``ciphertext`` with the provided private ``key``.

\ **Note:** The maximum size of accepted ciphertext is limited by the key size.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_encrypt:

.. rst-class:: classref-method

:ref:`PackedByteArray<class_PackedByteArray>` **encrypt** **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PackedByteArray<class_PackedByteArray>` plaintext **)**

Encrypt the given ``plaintext`` with the provided public ``key``.

\ **Note:** The maximum size of accepted plaintext is limited by the key size.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_generate_random_bytes:

.. rst-class:: classref-method

:ref:`PackedByteArray<class_PackedByteArray>` **generate_random_bytes** **(** :ref:`int<class_int>` size **)**

Generates a :ref:`PackedByteArray<class_PackedByteArray>` of cryptographically secure random bytes with given ``size``.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_generate_rsa:

.. rst-class:: classref-method

:ref:`CryptoKey<class_CryptoKey>` **generate_rsa** **(** :ref:`int<class_int>` size **)**

Generates an RSA :ref:`CryptoKey<class_CryptoKey>` that can be used for creating self-signed certificates and passed to :ref:`StreamPeerTLS.accept_stream<class_StreamPeerTLS_method_accept_stream>`.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_generate_self_signed_certificate:

.. rst-class:: classref-method

:ref:`X509Certificate<class_X509Certificate>` **generate_self_signed_certificate** **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`String<class_String>` issuer_name="CN=myserver,O=myorganisation,C=IT", :ref:`String<class_String>` not_before="20140101000000", :ref:`String<class_String>` not_after="20340101000000" **)**

Generates a self-signed :ref:`X509Certificate<class_X509Certificate>` from the given :ref:`CryptoKey<class_CryptoKey>` and ``issuer_name``. The certificate validity will be defined by ``not_before`` and ``not_after`` (first valid date and last valid date). The ``issuer_name`` must contain at least "CN=" (common name, i.e. the domain name), "O=" (organization, i.e. your company name), "C=" (country, i.e. 2 lettered ISO-3166 code of the country the organization is based in).

A small example to generate an RSA key and a X509 self-signed certificate.


.. tabs::

 .. code-tab:: gdscript

    var crypto = Crypto.new()
    # Generate 4096 bits RSA key.
    var key = crypto.generate_rsa(4096)
    # Generate self-signed certificate using the given key.
    var cert = crypto.generate_self_signed_certificate(key, "CN=example.com,O=A Game Company,C=IT")

 .. code-tab:: csharp

    var crypto = new Crypto();
    // Generate 4096 bits RSA key.
    CryptoKey key = crypto.GenerateRsa(4096);
    // Generate self-signed certificate using the given key.
    X509Certificate cert = crypto.GenerateSelfSignedCertificate(key, "CN=mydomain.com,O=My Game Company,C=IT");



.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_hmac_digest:

.. rst-class:: classref-method

:ref:`PackedByteArray<class_PackedByteArray>` **hmac_digest** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` key, :ref:`PackedByteArray<class_PackedByteArray>` msg **)**

Generates an `HMAC <https://en.wikipedia.org/wiki/HMAC>`__ digest of ``msg`` using ``key``. The ``hash_type`` parameter is the hashing algorithm that is used for the inner and outer hashes.

Currently, only :ref:`HashingContext.HASH_SHA256<class_HashingContext_constant_HASH_SHA256>` and :ref:`HashingContext.HASH_SHA1<class_HashingContext_constant_HASH_SHA1>` are supported.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_sign:

.. rst-class:: classref-method

:ref:`PackedByteArray<class_PackedByteArray>` **sign** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` hash, :ref:`CryptoKey<class_CryptoKey>` key **)**

Sign a given ``hash`` of type ``hash_type`` with the provided private ``key``.

.. rst-class:: classref-item-separator

----

.. _class_Crypto_method_verify:

.. rst-class:: classref-method

:ref:`bool<class_bool>` **verify** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PackedByteArray<class_PackedByteArray>` hash, :ref:`PackedByteArray<class_PackedByteArray>` signature, :ref:`CryptoKey<class_CryptoKey>` key **)**

Verify that a given ``signature`` for ``hash`` of type ``hash_type`` against the provided public ``key``.

.. |virtual| replace:: :abbr:`virtual (This method should typically be overridden by the user to have any effect.)`
.. |const| replace:: :abbr:`const (This method has no side effects. It doesn't modify any of the instance's member variables.)`
.. |vararg| replace:: :abbr:`vararg (This method accepts any number of arguments after the ones described here.)`
.. |constructor| replace:: :abbr:`constructor (This method is used to construct a type.)`
.. |static| replace:: :abbr:`static (This method doesn't need an instance to be called, so it can be called directly using the class name.)`
.. |operator| replace:: :abbr:`operator (This method describes a valid operator to use with this type as left-hand operand.)`