초록 ▼

A method for providing a digital signature, "chameleon signatures", which provide the signer of a digital signature exclusive control to disclose the contents of the signed information to third parties. The signatures are closely related to "undeniable signatures", but allow for simpler and more eff

A method for providing a digital signature, "chameleon signatures", which provide the signer of a digital signature exclusive control to disclose the contents of the signed information to third parties. The signatures are closely related to "undeniable signatures", but allow for simpler and more efficient realizations. The method is essentially non-interactive requiring no communication between sender and receiver and do not involve the design and complexity of zero knowledge proofs on which traditional undeniable signatures are based. The method employs a combination of standard digital signing methods with a unique hash functions. These hash functions are characterized by the non-standard property of being collision resistant for the signer but collision tractable for the recipient.

대표청구항 ▼

[ Having thus described our invention, what we claim as new, and desire to secure by Letters Patent is:] [1.] A method for providing a non-repudiable commitment of a signer to the contents of a digitally signed document, containing a message m, to a recipient, said method comprising the steps of:a)

[ Having thus described our invention, what we claim as new, and desire to secure by Letters Patent is:] [1.] A method for providing a non-repudiable commitment of a signer to the contents of a digitally signed document, containing a message m, to a recipient, said method comprising the steps of:a) the recipient generating public and private chameleon hash keys and a chameleon hash function;b) the signer generating a public verification key and a private signature key;c) the signer utilizing said chameleon hash function and said public chameleon hash key to compute a chameleon hash value of said message m;d) the signer applying said private signature key to said chameleon hash value to generate a chameleon signature of said message m;e) transmitting said chameleon signature and said message m to said recipient;f) verifying said chameleon signature for a message m using said chameleon hash function, said public chameleon hash key and said public verification key.