Update of "Experiment: mmmv_symsig_t1"
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Artifact ID: 982b416fde7b5508f03d5dd392ab79efc2bb9943
Page Name:Experiment: mmmv_symsig_t1
Date: 2017-10-08 22:39:31
Original User: martin_vahi
Parent: bfdb20c1b9a6c8c74fad9bb6b73443e8d7f4907e (diff)
Next 0790a4777474a301c4b5bd2fc390bcb1f6e553b1

The mmmv_symsig_t1 wraps symmetric key encryption command line tools and implements a signing system, where parties, who have never met directly for a key exchange can probabilistically authenticate each other. The feasibility of using one-time-pads or one-time-pad like ciphers is based on the fact that a year 2017 price for 1GiB of USB-stick based flash memory costs about 1€. With the exception of metadata related security issues, one-time-pad like ciphers tend to eliminate security flaws at the encryption algorithm side.

It's worth to note that if both keys of a public encryption algorithm are bundled together and the whole pair is kept secret the way  symmetric keys are kept secret, then public key encryption algorithms can be used as symmetric key encryption algorithms. That allows the "standard" tools like the GNU Privacy Guard to be used in the role of the symmetric key encryption algorithm implementation.

The Scheme

End users(hereafter: EnU), including the Bob and the Alice, individually meet with a key exchange service provider (hereafter: KXS). The KXS gives each EnU multiple GiB worth of symmetric keys that are shared only between the KXS and the EnU. If the EnUs have not met with each other for a key exchange, then the KXS forms a central hub that decrypts the ciphertext of one EnU and encrypts the cleartext for another EnU. That is to say, if the Bob and the Alice use only a single KXS, then the KXS acts like the Eve, when the Eve conducts a man-in-the-middle attack. To probabilistically counter the man-in-the-middle attack, the Bob and the Alice use the services of multiple KXS to agree a set of temporary encryption keys, one temporary key per one KXS. The Bob and the Alice use the temporary keys for onion-encrypting the actual data exchange between themselves. If at least 2 KXS-es keep the overheard temporary keys secret, then absolutely no KXS is able to decrypt the Bob's and Alice's onionencrypted session.

Optional Improvement Opportunities

In addition to the temporary keys that were overheard by the KXS, the Bob and the Alice may use additional temporary keys that they negotiated during previous sessions.