diff --git a/src/Model/TwoFactorRecoveryCode.php b/src/Model/TwoFactorRecoveryCode.php
index 82740d3b3c..74dead32d9 100644
--- a/src/Model/TwoFactorRecoveryCode.php
+++ b/src/Model/TwoFactorRecoveryCode.php
@@ -8,18 +8,45 @@ use Friendica\Util\DateTimeFormat;
 use PragmaRX\Random\Random;
 use PragmaRX\Recovery\Recovery;
 
+/**
+ * Manages users' two-factor recovery codes in the 2fa_recovery_codes table
+ *
+ * @package Friendica\Model
+ */
 class TwoFactorRecoveryCode extends BaseObject
 {
-	public static function countValidForUser($uid)
+    /**
+     * Returns the number of code the provided users can still use to replace a TOTP code
+     *
+     * @param int $uid User ID
+     * @return int
+     * @throws \Exception
+     */
+    public static function countValidForUser($uid)
 	{
 		return DBA::count('2fa_recovery_codes', ['uid' => $uid, 'used' => null]);
 	}
 
+    /**
+     * Checks the provided code is available to use for login by the provided user
+     *
+     * @param  int $uid User ID
+     * @param string $code
+     * @return bool
+     * @throws \Exception
+     */
 	public static function existsForUser($uid, $code)
 	{
 		return DBA::exists('2fa_recovery_codes', ['uid' => $uid, 'code' => $code, 'used' => null]);
 	}
 
+    /**
+     * Returns a complete list of all recovery codes for the provided user, including the used status
+     *
+     * @param  int $uid User ID
+     * @return array
+     * @throws \Exception
+     */
 	public static function getListForUser($uid)
 	{
 		$codesStmt = DBA::select('2fa_recovery_codes', ['code', 'used'], ['uid' => $uid]);
@@ -27,13 +54,29 @@ class TwoFactorRecoveryCode extends BaseObject
 		return DBA::toArray($codesStmt);
 	}
 
+    /**
+     * Marks the provided code as used for the provided user.
+     * Returns false if the code doesn't exist for the user or it has been used already.
+     *
+     * @param  int $uid User ID
+     * @param string $code
+     * @return bool
+     * @throws \Exception
+     */
 	public static function markUsedForUser($uid, $code)
 	{
-		DBA::update('2fa_recovery_codes', ['used' => DateTimeFormat::utcNow()], ['uid' => $uid, 'code' => $code]);
+		DBA::update('2fa_recovery_codes', ['used' => DateTimeFormat::utcNow()], ['uid' => $uid, 'code' => $code, 'used' => null]);
 
 		return DBA::affectedRows() > 0;
 	}
 
+    /**
+     * Generates a fresh set of recovery codes for the provided user.
+     * Generates 12 codes constituted of 2 blocks of 6 characters separated by a dash.
+     *
+     * @param  int $uid User ID
+     * @throws \Exception
+     */
 	public static function generateForUser($uid)
 	{
 		$Random = (new Random())->pattern('[a-z0-9]');
@@ -57,11 +100,23 @@ class TwoFactorRecoveryCode extends BaseObject
 		}
 	}
 
+    /**
+     * Deletes all the recovery codes for the provided user.
+     *
+     * @param  int $uid User ID
+     * @throws \Exception
+     */
 	public static function deleteForUser($uid)
 	{
 		DBA::delete('2fa_recovery_codes', ['uid' => $uid]);
 	}
 
+    /**
+     * Replaces the existing recovery codes for the provided user by a freshly generated set.
+     *
+     * @param  int $uid User ID
+     * @throws \Exception
+     */
 	public static function regenerateForUser($uid)
 	{
 		self::deleteForUser($uid);