An electronic signature is mandatory to guarantee authenticity and integrity. This is done via a digital certificate issued by a certification authority.
Furthermore, the use of a sequential numbering system is required, which, after being approved as an electronic invoice issuer, must be requested from DIAN. DIAN then issues a ranking and the digital control key, which is required to create the Código ùnico de Factura Electrónica (CUFE). THE CUFE consists of the concatenated data contained in the invoice and the control key allows easy identification and guarantees integrity. It is encrypted using a SHA1 algorithm.
Electronic invoices must be created in a special UBL (Universal Business Language) format, which is based on the XML standard.
Invoices must be stored for as long as specified in the tax law.