godot-docs/classes/class_crypto.rst

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.. DO NOT EDIT THIS FILE, but the Crypto.xml source instead.
.. The source is found in doc/classes or modules/<name>/doc_classes.

.. _class_Crypto:

Crypto
======

**Inherits:** :ref:`Reference<class_Reference>` **<** :ref:`Object<class_Object>`

Access to advanced cryptographic functionalities.

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

The Crypto class allows you to access some more advanced cryptographic functionalities in Godot.

For now, this includes generating cryptographically secure random bytes, RSA keys and self-signed X509 certificates generation, asymmetric key encryption/decryption, and signing/verification.

::

    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())
        # 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() == decrypted)

**Note:** Not available in HTML5 exports.

Methods
-------

+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`bool<class_bool>`                       | :ref:`constant_time_compare<class_Crypto_method_constant_time_compare>` **(** :ref:`PoolByteArray<class_PoolByteArray>` trusted, :ref:`PoolByteArray<class_PoolByteArray>` received **)**                                                                                                                                                     |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PoolByteArray<class_PoolByteArray>`     | :ref:`decrypt<class_Crypto_method_decrypt>` **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PoolByteArray<class_PoolByteArray>` ciphertext **)**                                                                                                                                                                                           |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PoolByteArray<class_PoolByteArray>`     | :ref:`encrypt<class_Crypto_method_encrypt>` **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PoolByteArray<class_PoolByteArray>` plaintext **)**                                                                                                                                                                                            |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PoolByteArray<class_PoolByteArray>`     | :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:`PoolByteArray<class_PoolByteArray>`     | :ref:`hmac_digest<class_Crypto_method_hmac_digest>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` key, :ref:`PoolByteArray<class_PoolByteArray>` msg **)**                                                                                                                         |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`PoolByteArray<class_PoolByteArray>`     | :ref:`sign<class_Crypto_method_sign>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` hash, :ref:`CryptoKey<class_CryptoKey>` key **)**                                                                                                                                              |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
| :ref:`bool<class_bool>`                       | :ref:`verify<class_Crypto_method_verify>` **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` hash, :ref:`PoolByteArray<class_PoolByteArray>` signature, :ref:`CryptoKey<class_CryptoKey>` key **)**                                                                                     |
+-----------------------------------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

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

.. _class_Crypto_method_constant_time_compare:

- :ref:`bool<class_bool>` **constant_time_compare** **(** :ref:`PoolByteArray<class_PoolByteArray>` trusted, :ref:`PoolByteArray<class_PoolByteArray>` received **)**

Compares two :ref:`PoolByteArray<class_PoolByteArray>`\ 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.

----

.. _class_Crypto_method_decrypt:

- :ref:`PoolByteArray<class_PoolByteArray>` **decrypt** **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PoolByteArray<class_PoolByteArray>` ciphertext **)**

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

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

----

.. _class_Crypto_method_encrypt:

- :ref:`PoolByteArray<class_PoolByteArray>` **encrypt** **(** :ref:`CryptoKey<class_CryptoKey>` key, :ref:`PoolByteArray<class_PoolByteArray>` plaintext **)**

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

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

----

.. _class_Crypto_method_generate_random_bytes:

- :ref:`PoolByteArray<class_PoolByteArray>` **generate_random_bytes** **(** :ref:`int<class_int>` size **)**

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

----

.. _class_Crypto_method_generate_rsa:

- :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:`StreamPeerSSL.accept_stream<class_StreamPeerSSL_method_accept_stream>`.

----

.. _class_Crypto_method_generate_self_signed_certificate:

- :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.

::

    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")

----

.. _class_Crypto_method_hmac_digest:

- :ref:`PoolByteArray<class_PoolByteArray>` **hmac_digest** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` key, :ref:`PoolByteArray<class_PoolByteArray>` 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.

----

.. _class_Crypto_method_sign:

- :ref:`PoolByteArray<class_PoolByteArray>` **sign** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` hash, :ref:`CryptoKey<class_CryptoKey>` key **)**

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

----

.. _class_Crypto_method_verify:

- :ref:`bool<class_bool>` **verify** **(** :ref:`HashType<enum_HashingContext_HashType>` hash_type, :ref:`PoolByteArray<class_PoolByteArray>` hash, :ref:`PoolByteArray<class_PoolByteArray>` 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.)`