Procedure for a multiple digital signatureIt comprises: i) generating, by a Trusted Third Party (T), a private key for each signer or member (F1, F2, . . . , Ft) of a group of signers (G); ii) generating, each of said signers (F1, F2, . . . , Ft), a partial signature of a document (M) using their private keys; iii) generating a multiple signature from said partial signatures; and iv) verifying said multiple signature. It further comprises generating, by the Trusted Third Party (T), a common public key for all of said signers (F1, F2, . . . , Ft) and using said common public key for performing said multiple signature verification of iv).