59 DeGarmo Hills Road
Wappingers Falls, NY 12590



NK-Crypt is a strong encryption system for securely exchanging messages. Unlike other secret key and public key encryption methods, NK-Crypt does not require any exchange or distribution of encryption keys. The sender and the receiver of a message each have their own secret keys for the message, but neither party knows the other party's key. The keys are never transmitted or distributed.

Today there are two leading methods for secret communication, secret key and public key. In secret key communication, both of the parties must have a copy of the secret key or keys used for each message. Keys must be distributed to all parties who need to communicate with one another, or who might need to communicate in the future.

In public key cryptography each party has a private key, which is never distributed, and a public key which must be distributed to everyone who wishes to communicate with them. For widespread use, there must be a key-issuing authority which possesses all of the public keys, and which distributes these keys to all participants.

With NK-Crypt's new method of communication, you and you alone have your keys. Your keys are never distributed to anyone, so there is no chance that anyone will ever intercept your keys. All of your keys are locked away on your computer under control of a Master Key that you choose, and that you alone know. The Master Key is not stored or recorded on the computer, so even if someone stole your computer, or copied your hard drive, they still would not be able to get your keys or read your messages.

With NK-Crypt you can establish secure communications with anyone else who has the NK-Crypt software. You can begin immediately. There is nothing to arrange in advance, other than agreeing that the sender and the receiver both use NK-Crypt. There is no need to send or receive keys, not secret keys, and not public keys.

Even if all of your emails were being read by an eavesdropper, even if all of your encrypted messages back and forth were intercepted, even if the intruder knew that you were using NK-Crypt, and even if your opponent also had the NK-Crypt software, your messages could not be read.

NK-Crypt uses a different key for every message, so even if one of the partners with whom you communicate were an enemy, or even if a message key were extracted from a partner's computer, this would not compromise your communications with any other party. Loss of one key will reveal only the one message sent with that key. It will not reveal any other messages, or even make it easier to decrypt other messages. Loss of all the keys used by one partner will not reveal any messages sent to or from other partners.

The standard version of NK-Crypt is available now for only $129. Shipping and handling within the U.S. is included, free. (New York state residents must add applicable sales tax.) Any two people with the standard version can communicate securely with each other. Nobody else, including other owners of the standard version, can read their messages.

The standard version of NK-Crypt is available now for only $129. Shipping and handling within the U.S. is included, free. (New York state residents must add applicable sales tax.) Two people with the SAME custom version can communicate securely with each other. Nobody else, including owners of the standard version, owners of other custom versions, and other owners of the SAME custom version can read their messages.


For more information see the
NK-Crypt User Manual

For general information about cryptography, see
Choosing an Encryption Product
A Quick Overview of Cryptography

The author of the NK-Crypt Message Encryption System is Dr. Frank Rubin, who has been involved with cryptography since 1957. He is the author of more than a dozen technical papers on cryptography (and several hobbyist articles that appeared in The Cryptogram). He was an editor of Cryptologia, a journal devoted to cryptology published at the United States Military Academy, West Point NY. Several of Frank Rubin's cryptographic papers are available on this website.

Quadratic Residue ciphers are compared to the RSA Public Key Cryptosystem
Uses a new one-way hashing function based on quadratic residues
A step by step approach to designing a strong stream cipher
Creates a digital signature that only the authorized signers could produce
A practical way to achieve near-perfect security

Here is a complete list of his cryptographic papers that have appeared in refereed journals.

Computer Methods for Decrypting Multiplex Ciphers. Cryptologia 2 (Apr. 1978), pp 152-160.

Computer Methods for Decrypting Random Stream Ciphers. Cryptologia 2 (July 1978), pp 215-231.

Decrypting a Stream Cipher Based on J-K Flip-flops. IEEE Trans. on Compu. 28 (July 1979), pp 483-487.
Reprinted in Cryptologia 5 (Jan. 1981), pp 51-57.

Solving a Cipher Based on Multiple Random Number Streams. Cryptologia 3 (July 1979), pp 155-157.

Cryptographic Aspects of Data Compression Codes. Cryptologia 3 (Oct. 1979), pp 202-205.

Foiling the Known-Plaintext Attack. Cryptologia 10 (Oct. 1986), pp 217-222.

Foiling an Exhaustive Key-Search Attack. Cryptologia 11 (Apr. 1987), pp 102-107.

The Cryptographic Uses of Post Tag Systems. Cryptologia 12 (Jan. 1988), pp 25-33.

Comments on "Cryptanalysis of Knapsack Ciphers Using Genetic Algorithms." Cryptologia 18 (Apr. 1994), pp 153-154.

The Quadratic and Double Quadratic Residue Ciphers. Cryptologia 19 (July 1995), pp 275-284.

Message Authentication Using Quadratic Residues. Cryptologia 19 (Oct. 1995), pp 397-404.

Designing a High-Security Cipher. Cryptologia 20 (July 1996), pp 247-257.

One-Time Pad Cryptography. Cryptologia 20 (Oct. 1996), pp 359-364.


Send email Send us an email for any comments or questions about the
NK-Crypt Message Encryption System.

© Copyright 2006, 2007 Master Software Corporation