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Public Key Encryption 3. Digital Signatures or The Box within a Box. Ken Coder sends Dee a secret message only she can unlock. It could have come from Pre Tender!. Yves Dropper's evil cousin. Ken's idea: Lock with my private key. Unlock with my public key: Only I could have sent it!.
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Public Key Encryption 3 Digital Signatures or The Box within a Box
It could have come from Pre Tender! Yves Dropper's evil cousin
Dee's Idea: Lock your box in a second one using my public key.
Digital Signatures • In any public key cryptosystem, one can implement digital signatures. • To send a signed message M from A to B using keys AE, AD, BE, BD: A sends cyphertext C = BE(AD(M)) B recovers text T = AE(BD(C)) T = AE(BD(BE(AD(M)))) = AE(AD(M)) = M A's Private Key B's private key
It's the law • Documents with Digital Signatures became legally binding in the United States in the year 2000.