Paper 2008/222

Encryption-On-Demand: Practical and Theoretical Considerations

Gideon Samid

Abstract

Alice and Bob may develop a spontaneous, yet infrequent need for online confidential exchange. They may be served by an 'encryption-on-demand' (EoD) service which will enable them to communicate securely with no prior preparations, and no after effects. We delineate a possible EoD service, and describe some of its theoretical and practical features. The proposed framework is a website which could tailor-make an encryption package to be downloaded by both Alice and Bob for their ad-hoc use. The downloaded package will include the cryptographic algorithm and a unique key, which may be of any size, since Alice and Bob will not have to enter, or regard the key per se, they would simply use the downloaded page to encrypt and decrypt their data. After their secure exchange both Alice and Bob may ignore, or discard the downloaded software, and restart the same procedure, with a different tailor-made package, exactly when needed. This framework allows for greater flexibility in managing the complexity aspects that ensures security. Alice and Bob will not have to know what encryption scheme they use. The server based tailoring program could pseudo-randomly pick AES, DES, RSA, ECC, select a short, or long key, and otherwise greatly increase the variability that would have to be negotiated by a cryptanalyst. Encryption-on-demand is offered on http://youdeny.com . Features are described.

Note: The described protocol is implemented on http://YouDeny.com, where the server tailors client encryption packages through server based PhP algorithms, while the client's package features autonmous encryption code implemented in JavaScript.