Crypto¶

Provides access to advanced cryptographic functionalities.

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 X509Certificates.

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)

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);
    }
}

Methods¶

bool	constant_time_compare ( PackedByteArray trusted, PackedByteArray received )
PackedByteArray	decrypt ( CryptoKey key, PackedByteArray ciphertext )
PackedByteArray	encrypt ( CryptoKey key, PackedByteArray plaintext )
PackedByteArray	generate_random_bytes ( int size )
CryptoKey	generate_rsa ( int size )
X509Certificate	generate_self_signed_certificate ( CryptoKey key, String issuer_name="CN=myserver,O=myorganisation,C=IT", String not_before="20140101000000", String not_after="20340101000000" )
PackedByteArray	hmac_digest ( HashType hash_type, PackedByteArray key, PackedByteArray msg )
PackedByteArray	sign ( HashType hash_type, PackedByteArray hash, CryptoKey key )
bool	verify ( HashType hash_type, PackedByteArray hash, PackedByteArray signature, CryptoKey key )

Method Descriptions¶

bool constant_time_compare ( PackedByteArray trusted, PackedByteArray received )

Compares two PackedByteArrays for equality without leaking timing information in order to prevent timing attacks.

See this blog post for more information.

PackedByteArray decrypt ( CryptoKey key, PackedByteArray ciphertext )

Decrypt the given ciphertext with the provided private key.

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

PackedByteArray encrypt ( CryptoKey key, PackedByteArray plaintext )

Encrypt the given plaintext with the provided public key.

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

PackedByteArray generate_random_bytes ( int size )

Generates a PackedByteArray of cryptographically secure random bytes with given size.

CryptoKey generate_rsa ( int size )

Generates an RSA CryptoKey that can be used for creating self-signed certificates and passed to StreamPeerTLS.accept_stream.

X509Certificate generate_self_signed_certificate ( CryptoKey key, String issuer_name="CN=myserver,O=myorganisation,C=IT", String not_before="20140101000000", String not_after="20340101000000" )

Generates a self-signed X509Certificate from the given 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")

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");

PackedByteArray hmac_digest ( HashType hash_type, PackedByteArray key, PackedByteArray msg )

Generates an 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 HashingContext.HASH_SHA256 and HashingContext.HASH_SHA1 are supported.

PackedByteArray sign ( HashType hash_type, PackedByteArray hash, CryptoKey key )

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

bool verify ( HashType hash_type, PackedByteArray hash, PackedByteArray signature, CryptoKey key )

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