Sorry,, its been awhile since I've looked at this.

The string encryption algorithm has been enhanced in its Visual Basic and Javascript implementations so that it uses a 64 key domain. The modified key used in the second round uses a randomly sorted set of key domain values. This improves the randomness in the output domain.

Using the new version requires 8-bit transmission as some values of the ciphertext may be outside of the common ASCII domain.

A slight fix was required for transmission of messages between different Windows versions shifting non-ASCII values to a range above 159 decimal. This avoids problems caused by transmission mediums and application hosts that have different implementations of the ISO-8859-1 character set.

The revised algorithm is implemented in Visual Basic and Javascript where it is employed to provide security for HTML textarea content in email. The E-mail attachments can be encrypted using CipherText or RijnDael.

CipherText has not been broken. Required is sophisticated analysis using parts of known plaintext and frequency analysis. Using a keystring of 20 values results in an applied pattern of cipher bits that does not repeat for 381 message values. A 2K textarea will yield only five values for each period location to frequency analysis. The algorithm also masks its root key so that if a message is somehow broken, the actual root is not revealed.

An updated version using the randomly sorted lookup table will be posted soon. I may also make an ASCII compatible version keeping with the restricted key domain and a randomly sorted set of 32 values in the lookup. This will be an improved implementation of the posted algorithm, but not nearly as strong as the new implementation that uses a 64 value key domain.

A Cryptologist tells me its quite difficult to analyse and admits that attacking it is very tedious. To date its not been done.

-C. Prichard

In reply to Re: CipherText by Steeeeeve
in thread CipherText by NodeReaper

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