Owncloud – Descifrar ficheros manualmente

Con el siguiente script se puede descrifrar el contenido de un fichero cifrado de owncloud.

El script php quedaría así:

<?php
 require_once 'crypt.php';

// first get users private key and decrypt it
 $encryptedUserKey = file_get_contents("/var/www/clients/client1/web1/web/data/user1/files_encryption/test.txt.private.key");
 $decryptedUserKey = OCA\Encryption\Crypt::decryptPrivateKey($encryptedUserKey, "admin");

// now we need to decrypt the file-key, therefore we use our private key and the share key
 $shareKey = file_get_contents("/var/www/clients/client1/web1/web/data/user1/files_encryption/share-keys/documents/test.txt.user1.shareKey");
 $encryptedKeyfile = file_get_contents("/var/www/clients/client1/web1/web/data/user1/files_encryption/keyfiles/documents/test.txt.key");
 $decryptedKeyfile = OCA\Encryption\Crypt::multiKeyDecrypt($encryptedKeyfile, $shareKey, $decryptedUserKey);

// finally we can use the decrypted file-key to decrypt the file
 $encryptedContent = file_get_contents("/var/www/clients/client1/web1/web/data/user1/files/documents/test.txt");
 $decryptedContent = OCA\Encryption\Crypt::symmetricDecryptFileContent($encryptedContent, $decryptedKeyfile);

//echo "result: " . $decryptedContent . "\n";
 echo $decryptedContent;
 ?>

Observaciones:

• Hay un require de crypt.php, se tiene que tener en cuenta ehhh 😉
• Se tiene que disponer de la private.key, del shareKey y del keyfile para poder realizar el descifrado.