<?xml version="1.0" encoding="UTF-8" ?>
<class name="Crypto" inherits="RefCounted" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
	<brief_description>
		Provides access to advanced cryptographic functionalities.
	</brief_description>
	<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 [X509Certificate]s.
		[codeblocks]
		[gdscript]
		var crypto = Crypto.new()

		# Generate new RSA key.
		var key = crypto.generate_rsa(4096)

		# Generate new self-signed certificate with the given key.
		var 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)
		[/gdscript]
		[csharp]
		using Godot;
		using System.Diagnostics;

		Crypto crypto = new Crypto();

		// Generate new RSA key.
		CryptoKey key = crypto.GenerateRsa(4096);

		// Generate new self-signed certificate with the given key.
		X509Certificate 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);
		[/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 an 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>
