Electronic signature software articles, schemes all have several prior requirements without which no such signature can mean anything, whatever the cryptographic theory or legal provision.

• First, quality algorithms. Electronic signature software articles, Some public key algorithms are known to be insecure, practicable attacks against them having been identified.
   
• Second, quality implementations. An implementation of a good algorithm (or protocol) with mistake(s) will not work.
   
• Third, the private key must remain actually secret; if it becomes known to some other party, that party can produce perfect digital signatures of anything whatsoever.
   
• Fourth, distribution of public keys must be done in such a way that the public key claimed to belong to Bob actually belongs to Bob, and vice versa. This is commonly done using a public key infrastructure and the public key-user association is attested by the operator of the PKI (called a certificate authority) Electronic signature software articles. For 'open' PKIs in which anyone can request such an attestation (universally embodied in an identity certificate), the possibility of mistake is non trivial. Commercial PKI operators have suffered several publicly known problems. Such mistakes could lead to falsely signed, and thus wrongly attributed, documents.
   
• Fifth, users (and their software) must carry out the signature protocol properly. - Electronic signature software articles.

Electronic signature software articles and digital signature guidelines.