From: (Robert  Egendorf)
Newsgroups: sci.crypt

Subject: Re: Algorithms
Date: 13 Nov 1994 00:37:02 GMT
Organization: University of Pennsylvania
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Message-ID: <3a3n3e$>
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Terry Ritter ( wrote:

:  2)  Cloak2 -- a 992-bit key, plus 992-bit message key, file cipher.
:           The mechanism is a two-level nonlinear Dynamic Substitution
:      combiner stream cipher, with 16 second-level combiners, and huge
:      nonlinearized RNG's.  The ciphertext is binary.

:  Both of the above are commercial secret-key ciphers currently
:  implemented for MSDOS (and which now function well under Microsoft
:  Windows).  They are not exportable.  But while the ciphers proper
:  are important, probably the major practical value of these systems
:  lies in extensive key-management by open alias, with the ability
:  to cleanly update keys without disturbing most users.  Central key
:  management can be important to allow a business to retain access
:  to information for which it originally paid.  And archived
:  ciphertext under old, replaced keys can be accessed easily.

:  For example, I used a 992-bit key (over 10 times as *long* as
:  an 80-bit "large enough" secret key) in my Cloak2 stream cipher,
:  because it was a reasonably clean design without too much overhead.
:  Since that design uses an RNG with about 37.8K (Bytes) of state,
:  I could instead "easily" equip it to use honest 310,048-bit keys,
:  provided we are willing to generate and keep such keys.  (The user
:  keys would be kept inside enciphered alias files, of course, but a
:  40K message key on a 2K message might seem a little much.)

Has anyone else evaluated the Cloak2 cipher?  What tests has it been 
subjected to?  What is Mr. Ritter's background in cryptography?