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diff --git a/XHubSignature.php b/XHubSignature.php
new file mode 100644
index 0000000..ad2e645
--- /dev/null
+++ b/XHubSignature.php
@@ -0,0 +1,151 @@
+<?php
+
+namespace Keruald\GitHub;
+
+class XHubSignature {
+
+ ///
+ /// Properties
+ ///
+
+ /**
+ * The secret token to secure messages
+ *
+ * @var string
+ */
+ private $secret;
+
+ /**
+ * The hash algorithm
+ *
+ * @var string
+ */
+ private $hashAlgo;
+
+ /**
+ * The payload
+ *
+ * @var string
+ */
+ public $payload;
+
+ /**
+ * The signature delivered with the payload, to validate it
+ *
+ * @var string
+ */
+ public $signature;
+
+ ///
+ /// Constants
+ ///
+
+ /**
+ * The default hash algorithm to use if none is offered
+ */
+ const DEFAULT_HASH_ALGO = 'sha1';
+
+ ///
+ /// Constructor
+ ///
+
+ /**
+ * Initializes a new instance of the XHubSignature class
+ *
+ * @param string $secret the secret token
+ * @param string $algo the algorithm to use to compute hashs [facultative]
+ */
+ public function __construct ($secret, $algo = self::DEFAULT_HASH_ALGO) {
+ $this->secret = $secret;
+ $this->hashAlgo = $algo;
+ }
+
+ ///
+ /// Signature methods
+ ///
+
+ /**
+ * Computes the signature for the current payload
+ *
+ * @return string the payload signature
+ */
+ public function compute () {
+ return hash_hmac($this->hashAlgo, $this->payload, $this->secret);
+ }
+
+ /**
+ * Validates the signature
+ *
+ * @return bool true if the signature is correct; otherwise, false.
+ */
+ public function validate () {
+ // Comparison with hash_equals allows to mitigate timing attacks.
+ return hash_equals($this->compute(), $this->signature);
+ }
+
+ ///
+ /// Static helper methods
+ ///
+
+ /**
+ * Computes a signature for the specified secret and payload
+ *
+ * @param string $secret the secret token to secure messages
+ * @param string $payload the payload
+ * @param string $algo the hash algorithm [facultative]
+ *
+ * @return string the payload signature
+ */
+ public static function hashPayload(
+ $secret,
+ $payload,
+ $algo = self::DEFAULT_HASH_ALGO
+ ) {
+ $instance = new static($secret, $algo);
+ $instance->payload = $payload;
+
+ return $instance->compute();
+ }
+
+ /**
+ * Validates a payload against specified secret
+ *
+ * @param string $secret the secret token to secure messages
+ * @param string $payload the payload
+ * @param string $signature the signature delivered with the payload
+ * @param string $algo the hash algorithm [facultative]
+ *
+ * @return bool true if the signature is correct; otherwise, false.
+ */
+ public static function validatePayload (
+ $secret,
+ $payload,
+ $signature,
+ $algo = self::DEFAULT_HASH_ALGO
+ ) {
+ $instance = new static($secret, $algo);
+ $instance->payload = $payload;
+ $instance->signature = $signature;
+
+ return $instance->validate();
+ }
+
+ /**
+ * Parses a X-Hub-Signature field from headers and gets the signature part
+ *
+ * @param string $header the header value
+ * @return string the signature
+ */
+ public static function parseSignature ($header) {
+ if ($header === null) {
+ return "";
+ }
+
+ if (strpos($header, '=') === false) {
+ return $header;
+ }
+
+ $data = explode('=', $header, 2);
+ return $data[1];
+ }
+}

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