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cse4707-secure-messaging/app/model/SecureMessage.php
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<?php | |
include_once(APP_DIR . 'database/Database.php'); | |
include_once(APP_DIR . 'config/config.php'); | |
include_once(APP_DIR . 'model/User.php'); | |
class SecureMessage { | |
protected static $table = 'messages'; | |
public $id; | |
public $message; | |
public $sender_id; | |
public $receiver_id; | |
public $is_read = false; | |
/** | |
* Stores this information pertaining to this message in the DB | |
*/ | |
public function save() { | |
$dbh = Database::connect(); | |
if (SecureMessage::exists($this->id)) { | |
$stmt = $dbh->prepare("UPDATE messages SET is_read=:is_read WHERE id=:message_id"); | |
$is_read = (int) $this->is_read; | |
$stmt->bindParam(':is_read', $is_read); | |
$stmt->bindParam(':message_id', $this->id); | |
$stmt->execute(); | |
return; | |
} | |
$integrity_key = openssl_random_pseudo_bytes(16); | |
$encryption_key = openssl_random_pseudo_bytes(16); | |
$message_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length(Config::encr_algo)); | |
$message_hash = hash_hmac(Config::hash_algo, $this->message, $integrity_key); | |
$ciphertext = openssl_encrypt($this->message . $message_hash, Config::encr_algo, $encryption_key, 0, $message_iv); | |
$keys_iv = openssl_random_pseudo_bytes(openssl_cipher_iv_length(Config::encr_algo)); | |
$enc_keys = openssl_encrypt($integrity_key . $encryption_key, Config::encr_algo, Config::secret_key, 0, $keys_iv); | |
$stmt = $dbh->prepare('INSERT INTO messages (message, sender_id, receiver_id, enc_keys, keys_iv, message_iv) | |
VALUES (:message, :sender_id, :receiver_id, :enc_keys, :keys_iv, :message_iv) | |
'); | |
$encoded_keys_iv = base64_encode($keys_iv); | |
$encoded_message_iv = base64_encode($message_iv); | |
$stmt->bindParam(':message', $ciphertext); | |
$stmt->bindParam(':sender_id', $this->sender_id); | |
$stmt->bindParam(':receiver_id', $this->receiver_id); | |
$stmt->bindParam(':enc_keys', $enc_keys); | |
$stmt->bindParam(':keys_iv', $encoded_keys_iv); | |
$stmt->bindParam(':message_iv', $encoded_message_iv); | |
$stmt->execute(); | |
$this->id = $dbh->lastInsertId(); | |
} | |
public function delete() { | |
$dbh = Database::connect(); | |
$stmt = $dbh->prepare("DELETE FROM messages WHERE id=:id"); | |
$stmt->bindParam(':id', $this->id); | |
$stmt->execute(); | |
} | |
public static function exists($message_id) { | |
$dbh = Database::connect(); | |
$stmt = $dbh->prepare("SELECT count(*) FROM messages WHERE id = :message_id"); | |
$stmt->bindParam(':message_id', $message_id); | |
$stmt->execute(); | |
return $stmt->fetchColumn() > 0; | |
} | |
public static function getByID($message_id) { | |
$messages = SecureMessage::all(); | |
foreach ($messages as $m) { | |
if ($m->id == $message_id) { | |
return $m; | |
} | |
} | |
return null; | |
} | |
public static function all() { | |
$dbh = Database::connect(); | |
$stmt = $dbh->prepare("SELECT * from messages"); | |
$stmt->execute(); | |
$messages = array_map(function ($row) { | |
$m = new SecureMessage; | |
$keys_iv = base64_decode($row['keys_iv']); | |
$message_iv = base64_decode($row['message_iv']); | |
/* Decrypt to get the keys */ | |
$keys = openssl_decrypt($row['enc_keys'], Config::encr_algo, Config::secret_key, 0, $keys_iv); | |
$integrity_key = substr($keys, 0, strlen($keys) / 2); | |
$message_key = substr($keys, strlen($keys) / 2); | |
/* Decrypt and extract the message and hash */ | |
$decrypted = openssl_decrypt($row['message'], Config::encr_algo, $message_key, 0, $message_iv); | |
$message = substr($decrypted, 0, strlen($decrypted) - 64); | |
$message_hash = substr($decrypted, strlen($decrypted) - 64); | |
/* Verify integrity of message */ | |
if (hash_hmac(Config::hash_algo, $message, $integrity_key) != $message_hash) { | |
return null; | |
} | |
$m->id = $row['id']; | |
$m->message = $message; | |
$m->sender_id = $row['sender_id']; | |
$m->receiver_id = $row['receiver_id']; | |
$m->is_read = (bool) $row['is_read']; | |
return $m; | |
}, $stmt->fetchAll()); | |
/* Filter out bad messages */ | |
return array_filter($messages, function ($m) { | |
return $m != null; | |
}); | |
} | |
public static function all_from($user_id) { | |
$messages = SecureMessage::all(); | |
return array_filter($messages, function ($m) use ($user_id) { | |
return $m->sender_id == $user_id; | |
}); | |
} | |
public static function all_to($user_id) { | |
$messages = SecureMessage::all(); | |
return array_filter($messages, function ($m) use ($user_id) { | |
return $m->receiver_id == $user_id; | |
}); | |
} | |
public static function all_for($user_id) { | |
$messages = SecureMessage::all(); | |
return array_filter($messages, function ($m) use ($user_id) { | |
return $m->sender_id == $user_id || $m->receiver_id = $user_id; | |
}); | |
} | |
public static function count_unread($user_id) { | |
$messages = SecureMessage::all(); | |
return count(array_filter($messages, function ($m) use ($user_id) { | |
return $m->receiver_id == $user_id && ! $m->is_read; | |
})); | |
} | |
public function sender() { | |
return User::getByID($this->sender_id); | |
} | |
public function receiver() { | |
return User::getByID($this->receiver_id); | |
} | |
} | |
?> |