godot/doc/classes/Crypto.xml

<?xml version="1.0" encoding="UTF-8" ?>
<class name="Crypto" inherits="RefCounted" version="4.1" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
	<brief_description>
		Access to advanced cryptographic functionalities.
	</brief_description>
	<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.
		[codeblocks]
		[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())
		    # 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)
		[/gdscript]
		[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.ToUtf8());
		        // 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.ToUtf8() == decrypted);
		    }
		}
		[/csharp]
		[/codeblocks]
	</description>
	<tutorials>
	</tutorials>
	<methods>
		<method name="constant_time_compare">
			<return type="bool" />
			<param index="0" name="trusted" type="PackedByteArray" />
			<param index="1" name="received" type="PackedByteArray" />
			<description>
				Compares two [PackedByteArray]s for equality without leaking timing information in order to prevent timing attacks.
				See [url=https://paragonie.com/blog/2015/11/preventing-timing-attacks-on-string-comparison-with-double-hmac-strategy]this blog post[/url] for more information.
			</description>
		</method>
		<method name="decrypt">
			<return type="PackedByteArray" />
			<param index="0" name="key" type="CryptoKey" />
			<param index="1" name="ciphertext" type="PackedByteArray" />
			<description>
				Decrypt the given [param ciphertext] with the provided private [param key].
				[b]Note:[/b] The maximum size of accepted ciphertext is limited by the key size.
			</description>
		</method>
		<method name="encrypt">
			<return type="PackedByteArray" />
			<param index="0" name="key" type="CryptoKey" />
			<param index="1" name="plaintext" type="PackedByteArray" />
			<description>
				Encrypt the given [param plaintext] with the provided public [param key].
				[b]Note:[/b] The maximum size of accepted plaintext is limited by the key size.
			</description>
		</method>
		<method name="generate_random_bytes">
			<return type="PackedByteArray" />
			<param index="0" name="size" type="int" />
			<description>
				Generates a [PackedByteArray] of cryptographically secure random bytes with given [param size].
			</description>
		</method>
		<method name="generate_rsa">
			<return type="CryptoKey" />
			<param index="0" name="size" type="int" />
			<description>
				Generates an RSA [CryptoKey] that can be used for creating self-signed certificates and passed to [method StreamPeerTLS.accept_stream].
			</description>
		</method>
		<method name="generate_self_signed_certificate">
			<return type="X509Certificate" />
			<param index="0" name="key" type="CryptoKey" />
			<param index="1" name="issuer_name" type="String" default="&quot;CN=myserver,O=myorganisation,C=IT&quot;" />
			<param index="2" name="not_before" type="String" default="&quot;20140101000000&quot;" />
			<param index="3" name="not_after" type="String" default="&quot;20340101000000&quot;" />
			<description>
				Generates a self-signed [X509Certificate] from the given [CryptoKey] and [param issuer_name]. The certificate validity will be defined by [param not_before] and [param not_after] (first valid date and last valid date). The [param 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.
				[codeblocks]
				[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")
				[/gdscript]
				[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");
				[/csharp]
				[/codeblocks]
			</description>
		</method>
		<method name="hmac_digest">
			<return type="PackedByteArray" />
			<param index="0" name="hash_type" type="int" enum="HashingContext.HashType" />
			<param index="1" name="key" type="PackedByteArray" />
			<param index="2" name="msg" type="PackedByteArray" />
			<description>
				Generates an [url=https://en.wikipedia.org/wiki/HMAC]HMAC[/url] digest of [param msg] using [param key]. The [param hash_type] parameter is the hashing algorithm that is used for the inner and outer hashes.
				Currently, only [constant HashingContext.HASH_SHA256] and [constant HashingContext.HASH_SHA1] are supported.
			</description>
		</method>
		<method name="sign">
			<return type="PackedByteArray" />
			<param index="0" name="hash_type" type="int" enum="HashingContext.HashType" />
			<param index="1" name="hash" type="PackedByteArray" />
			<param index="2" name="key" type="CryptoKey" />
			<description>
				Sign a given [param hash] of type [param hash_type] with the provided private [param key].
			</description>
		</method>
		<method name="verify">
			<return type="bool" />
			<param index="0" name="hash_type" type="int" enum="HashingContext.HashType" />
			<param index="1" name="hash" type="PackedByteArray" />
			<param index="2" name="signature" type="PackedByteArray" />
			<param index="3" name="key" type="CryptoKey" />
			<description>
				Verify that a given [param signature] for [param hash] of type [param hash_type] against the provided public [param key].
			</description>
		</method>
	</methods>
</class>