Added doc comments on Salmon magicsig-related stuff to help in figuring out what's going on

plugins/OStatus/classes/Magicsig.php

@@ -39,11 +39,41 @@ class Magicsig extends Memcached_DataObject
 
     public $__table = 'magicsig';
 
+    /**
+     * Key to user.id/profile.id for the local user whose key we're storing.
+     *
+     * @var int
+     */
     public $user_id;
+
+    /**
+     * Flattened string representation of the key pair; callers should
+     * usually use $this->publicKey and $this->privateKey directly,
+     * which hold live Crypt_RSA key objects.
+     *
+     * @var string
+     */
     public $keypair;
+
+    /**
+     * Crypto algorithm used for this key; currently only RSA-SHA256 is supported.
+     *
+     * @var string
+     */
     public $alg;
 
+    /**
+     * Public RSA key; gets serialized in/out via $this->keypair string.
+     *
+     * @var Crypt_RSA
+     */
     public $publicKey;
+
+    /**
+     * PrivateRSA key; gets serialized in/out via $this->keypair string.
+     *
+     * @var Crypt_RSA
+     */
     public $privateKey;
 
     public function __construct($alg = 'RSA-SHA256')
@@ -51,6 +81,13 @@ class Magicsig extends Memcached_DataObject
         $this->alg = $alg;
     }
 
+    /**
+     * Fetch a Magicsig object from the cache or database on a field match.
+     *
+     * @param string $k
+     * @param mixed $v
+     * @return Magicsig
+     */
     public /*static*/ function staticGet($k, $v=null)
     {
         $obj =  parent::staticGet(__CLASS__, $k, $v);
@@ -103,6 +140,14 @@ class Magicsig extends Memcached_DataObject
         return array(false, false, false);
     }
 
+    /**
+     * Save this keypair into the database.
+     *
+     * Overloads default insert behavior to encode the live key objects
+     * as a flat string for storage.
+     *
+     * @return mixed
+     */
     function insert()
     {
         $this->keypair = $this->toString();
@@ -110,6 +155,14 @@ class Magicsig extends Memcached_DataObject
         return parent::insert();
     }
 
+    /**
+     * Generate a new keypair for a local user and store in the database.
+     *
+     * Warning: this can be very slow on systems without the GMP module.
+     * Runtimes of 20-30 seconds are not unheard-of.
+     *
+     * @param int $user_id id of local user we're creating a key for
+     */
     public function generate($user_id)
     {
         $rsa = new Crypt_RSA();
@@ -128,6 +181,12 @@ class Magicsig extends Memcached_DataObject
         $this->insert();
     }
 
+    /**
+     * Encode the keypair or public key as a string.
+     *
+     * @param boolean $full_pair set to false to leave out the private key.
+     * @return string
+     */
     public function toString($full_pair = true)
     {
         $mod = Magicsig::base64_url_encode($this->publicKey->modulus->toBytes());
@@ -140,6 +199,13 @@ class Magicsig extends Memcached_DataObject
         return 'RSA.' . $mod . '.' . $exp . $private_exp;
     }
 
+    /**
+     * Decode a string representation of an RSA public key or keypair
+     * as a Magicsig object which can be used to sign or verify.
+     *
+     * @param string $text
+     * @return Magicsig
+     */
     public static function fromString($text)
     {
         $magic_sig = new Magicsig();
@@ -168,6 +234,14 @@ class Magicsig extends Memcached_DataObject
         return $magic_sig;
     }
 
+    /**
+     * Fill out $this->privateKey or $this->publicKey with a Crypt_RSA object
+     * representing the give key (as mod/exponent pair).
+     *
+     * @param string $mod base64-encoded
+     * @param string $exp base64-encoded exponent
+     * @param string $type one of 'public' or 'private'
+     */
     public function loadKey($mod, $exp, $type = 'public')
     {
         common_log(LOG_DEBUG, "Adding ".$type." key: (".$mod .', '. $exp .")");
@@ -186,11 +260,22 @@ class Magicsig extends Memcached_DataObject
         }
     }
 
+    /**
+     * Returns the name of the crypto algorithm used for this key.
+     *
+     * @return string
+     */
     public function getName()
     {
         return $this->alg;
     }
 
+    /**
+     * Returns the name of a hash function to use for signing with this key.
+     *
+     * @return string
+     * @fixme is this used? doesn't seem to be called by name.
+     */
     public function getHash()
     {
         switch ($this->alg) {
@@ -200,24 +285,48 @@ class Magicsig extends Memcached_DataObject
         }
     }
 
+    /**
+     * Generate base64-encoded signature for the given byte string
+     * using our private key.
+     *
+     * @param string $bytes as raw byte string
+     * @return string base64-encoded signature
+     */
     public function sign($bytes)
     {
         $sig = $this->privateKey->sign($bytes);
         return Magicsig::base64_url_encode($sig);
     }
 
+    /**
+     *
+     * @param string $signed_bytes as raw byte string
+     * @param string $signature as base64
+     * @return boolean
+     */
     public function verify($signed_bytes, $signature)
     {
         $signature = Magicsig::base64_url_decode($signature);
         return $this->publicKey->verify($signed_bytes, $signature);
     }
 
-
+    /**
+     * URL-encoding-friendly base64 variant encoding.
+     *
+     * @param string $input
+     * @return string
+     */
     public static function base64_url_encode($input)
     {
         return strtr(base64_encode($input), '+/', '-_');
     }
 
+    /**
+     * URL-encoding-friendly base64 variant decoding.
+     *
+     * @param string $input
+     * @return string
+     */
     public static function base64_url_decode($input)
     {
         return base64_decode(strtr($input, '-_', '+/'));