A method for automatically encrypting files is disclosed. In some cases, the method may be performed by computer hardware comprising one or more processors. The method can include detecting access to a first file, which may be stored in a primary storage system. Further, the method can include determining whether the access comprises a write access. In response to determining that the access comprises a write access, the method can include accessing file metadata associated with the first file and accessing a set of encryption rules. In addition, the method can include determining whether the file metadata satisfies the set of encryption rules. In response to determining that the file metadata satisfies the set of encryption rules, the method can include encrypting the first file to obtain a first encrypted file and modifying an extension of the first encrypted file to include an encryption extension.