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Digital Signatures. Written Signatures / Paper Documents. Provide “proof” of identification Legal basis – contracts, etc. Ceremonial – signing person knows when s/he enters a contract. But. Forgery Falsified ID Altered documents Insecure – couriers, agencies, secretaries. Therefore:.
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Written Signatures / Paper Documents • Provide “proof” of identification • Legal basis – contracts, etc. • Ceremonial – signing person knows when s/he enters a contract
But . . . • Forgery • Falsified ID • Altered documents • Insecure – couriers, agencies, secretaries
Therefore: • Digital Signatures!!! • Short history • Technology • How to . . .
Short history of digital signatures • DSS - Federal Information Processing Standards Publications (FIPS PUBS) – publication 186: May 19, 1994 • The standard (DSS) specifies a DSA appropriate for applications requiring a digital rather than a written signature • Specifications also in this document
Technology • Dig. sig. computed such that identity of signatory and integrity of data can be verified • Public/private keys – encode with private, verify with public • This ensures a nonrepudiation policy, as well – once message has been verified, signatory cannot repudiate involvement with message/contract
Tech. (cont.) • Encryption can also be accomplished using many modern software packages (PGP, for example) – sign and encrypt with private keys • De-encryption and verification by public keys
How to . . . • To use such technology, get digital signing/encryption software • PGP (Pretty Good Privacy) (www.pgpi.org) • Fairly well known • Offers many features • E-mail encryption • Instant Message encryption (using MSN Messenger) • PGPNet – all network communications can be encrypted • Search engine – “Digital Signature” or “Encryption”
Sources: • http://www.itl.nist.gov/fipspubs/fip186.htm (Federal Information Processing Standards Publications) • http://www.abanet.org/scitech/ec/isc/dsg-tutorial.html (American Bar Association - Digital Signature Guidelines Tutorial) • http://www.pgpi.org/ (International PGP Home Page) • http://web.mit.edu/network/pgp.html (MIT distribution site for PGP)