1 files changed, 91 insertions, 0 deletions
diff --git a/Zotlabs/Lib/JcsEddsa2022.php b/Zotlabs/Lib/JcsEddsa2022.php
new file mode 100644
index 000000000..cb5462952
--- /dev/null
+++ b/Zotlabs/Lib/JcsEddsa2022.php
@@ -0,0 +1,91 @@
+<?php
+
+namespace Zotlabs\Lib;
+
+use Mmccook\JsonCanonicalizator\JsonCanonicalizatorFactory;
+use StephenHill\Base58;
+
+class JcsEddsa2022 {
+
+	public  function  __construct() {
+		return $this;
+	}
+
+	public function sign($data, $channel): array {
+		$base58 = new Base58();
+		$pubkey = (new Multibase())->publicKey($channel['channel_epubkey']);
+		$options = [
+			'type' => 'DataIntegrityProof',
+			'cryptosuite' => 'eddsa-jcs-2022',
+			'created' => datetime_convert(format: ATOM_TIME),
+			'verificationMethod' => channel_url($channel) . '#' . $pubkey,
+			'proofPurpose' => 'assertionMethod',
+		];
+
+		$optionsHash = $this->hash($this->signableOptions($options), true);
+		$dataHash = $this->hash($this->signableData($data), true);
+
+		$options['proofValue'] = 'z' . $base58->encode(sodium_crypto_sign_detached($optionsHash . $dataHash,
+				sodium_base642bin($channel['channel_eprvkey'], SODIUM_BASE64_VARIANT_ORIGINAL_NO_PADDING)));
+
+		return $options;
+	}
+
+	public function verify($data, $publicKey) {
+		$base58 = new Base58();
+		$encodedSignature = $data['proof']['proofValue'] ?? '';
+		if (!str_starts_with($encodedSignature,'z')) {
+			return false;
+		}
+		$encodedSignature = substr($encodedSignature, 1);
+		$optionsHash = $this->hash($this->signableOptions($data['proof']), true);
+		$dataHash = $this->hash($this->signableData($data),true);
+
+		try {
+			$result = sodium_crypto_sign_verify_detached($base58->decode($encodedSignature), $optionsHash . $dataHash,
+				(new Multibase())->decode($publicKey, true));
+		}
+		catch (\Exception $e) {
+			logger('verify exception:' .  $e->getMessage());
+		}
+
+		logger('SignatureVerify (eddsa-jcs-2022) ' . (($result) ? 'true' : 'false'));
+
+		return $result;
+	}
+
+	public function signableData($data) {
+		$signableData = [];
+		if ($data) {
+			foreach ($data as $k => $v) {
+				if ($k != 'proof') {
+					$signableData[$k] = $v;
+				}
+			}
+		}
+		return $signableData;
+	}
+
+	public function signableOptions($options) {
+		$signableOptions = [];
+
+		if ($options) {
+			foreach ($options as $k => $v) {
+				if ($k !== 'proofValue') {
+					$signableOptions[$k] = $v;
+				}
+			}
+		}
+		return $signableOptions;
+	}
+
+	public function hash($obj, $binary = false) {
+		return hash('sha256', $this->canonicalize($obj), $binary);
+	}
+
+	public function canonicalize($data) {
+		$canonicalization = JsonCanonicalizatorFactory::getInstance();
+		return $canonicalization->canonicalize($data);
+	}
+
+}