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<?xml version="1.0" encoding="UTF-8" ?>
<class name="Crypto" inherits="RefCounted" version="4.0" 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=""CN=myserver,O=myorganisation,C=IT"" />
<param index="2" name="not_before" type="String" default=""20140101000000"" />
<param index="3" name="not_after" type="String" default=""20340101000000"" />
<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>
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