Abstract: Procedure for a multiple digital signature It 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).

Abstract: It 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).

Abstract: Systems and methods for using cryptographic keys read an existing digital certificate from a hardware cryptographic device and extract a public key from the existing digital certificate. A certificate request message is generated that identifies a new usage and/or certificate field associated with the public key. The certificate request message is signed and communicated to a certification authority. A new digital certificate is received from the certification authority that includes the new usage/field. The new digital certificate is then applied to cryptographic operations, such as signing procedures, encryption procedures and so forth using the existing key pair.