Re: Encryption algorithm

From: Russell Styles (rNwOsS0P2A0M2_at_comcast.net)
Date: 01/09/04 

Date: Fri, 9 Jan 2004 17:43:55 -0500

    I also use this method, but be aware that it can be broken. Ie, if you
use
it to encrypt a password in a configuration file, it will likely have
trailing spaces,
which would be the same every time.

    But it is quick and easy.

    Note that you don't need to differentiate between encrpt and decrypt.
It
works both ways. Eg, if you do it twice with the same password, you get
the original clear text back.

"Peter E.C. Dashwood" <dashwood@enternet.co.nz> wrote in message
news:3ffc7d3e_6@news.athenanews.com...
>
> "Vik Mehta" <aul1231@yahoo.com> wrote in message
> news:2df8b8ca.0401070700.67c3ec95@posting.google.com...
> > I am looking for a simple encryption algorithm to encrypt a 13
> > character alphanumeric string in a COBOL program. Any help will be
> > appreciated.
> >
>
> Presumably you want the encryption as a COBOL Subroutine?
>
> You will need a COBOL compiler that supports the XOR function.
>
> (Microfus and Fujitsu do.)
>
> "Here's one I prepared earlier..." (MUCH earlier...over 6 years ago, in
> fact. It works extremely well despite being simple, and is ideal for short
> strings that need encryption before writing to a database or file (like
> passwords).)
>
> Remove anything in square brackets "[...]" before compiling.
>
> IDENTIFICATION DIVISION.
> PROGRAM-ID. 'HERACrpt'.
> *AUTHOR. Peter E. C. Dashwood.
> * This program encrypts/decrypts an 8 byte password.
> *
> *DATE_WRITTEN. August 1997.
> ENVIRONMENT DIVISION.
> configuration section.
> source-computer. IBM-PC.
> object-computer. IBM-PC.
> *------------------------ DATA DIVISION ----------------------
> DATA DIVISION.
> WORKING-STORAGE SECTION.
> 01 encryption-key pic x(8) value 'ANYTHING'.
>
> [You can set this key to be any character string you like. My applications
> do not use "ANYTHING"... It must be the same length as the field you wish
to
> encrypt, so in your case you need to make it 13 bytes and set a value in
it.
> (I suggest: ANYTHINGULIKE while you are testing it...<G> This encryption
> key can be any combination of characters you like. You don't have to
> remember it, but you should make sure that the source code of your
> encryption module is not freely available, for obvious reasons. (You could
> save it as an encrypted WORD document <G>)]
>
> 01 xor-return-code pic s9(4) comp-5.
> 01 hex-table.
> 12 filler pic x value '0'.
> 12 filler pic x value '1'.
> 12 filler pic x value '2'.
> 12 filler pic x value '3'.
> 12 filler pic x value '4'.
> 12 filler pic x value '5'.
> 12 filler pic x value '6'.
> 12 filler pic x value '7'.
> 12 filler pic x value '8'.
> 12 filler pic x value '9'.
> 12 filler pic x value 'A'.
> 12 filler pic x value 'B'.
> 12 filler pic x value 'C'.
> 12 filler pic x value 'D'.
> 12 filler pic x value 'E'.
> 12 filler pic x value 'F'.
> 01 filler redefines hex-table.
> 12 hex-values pic x occurs 16
> indexed by hv-x1.
>
> 01 ws-byte-stuff.
> 12 filler pic x.
> 12 lod-byte pic x.
> 01 ws-binary redefines ws-byte-stuff pic s9(4) comp.
>
> 01 quotient pic 99.
> 01 rem pic 99.
>
> 01 num pic s9(5) comp-5.
>
> 01 two-bytes.
> 12 hod-hex pic x.
> 12 lod-hex pic x.
>
> 01 work-string.
> 12 ws-char pic x occurs 16
> indexed by ws-x1.
> 01 xor-len pic s9(9) comp-5.
>
>
> LINKAGE SECTION.
>
> [The module takes a single parameter that includes a return code, an
> indication whether to ENCRYPT or DECRYPT (there's not much point
encrypting
> stuff if you can't decrypt it...) and a passed string that will be 26
bytes
> in your case (It is twice the length of the string you want encrypted, as
it
> must return each encrypted character as a hex byte.i.e. 2 bytes per byte
of
> source)]
>
> 01 encryption-block.
> 12 eb-return pic x.
> 88 eb-ok value zero.
> 88 eb-bad-action value '1'.
> 88 eb-bad-char value '2'.
> 12 eb-action pic x.
> 88 HeraEncrypting value 'E'.
> 88 HeraDecrypting value 'D'.
> 12 eb-string pic x(16).
>
> PROCEDURE DIVISION USING Encryption-block.
> MAIN SECTION.
> a000.
> move zero to xor-len
> inspect eb-string
> tallying xor-len for
> characters BEFORE space
>
> evaluate TRUE
> when HeraEncrypting
> perform xorit
> perform asc2hex
> when HeraDecrypting
> perform hex2asc
> perform xorit
> when other
> set eb-bad-action to TRUE
> end-evaluate
> .
> a999.
> exit program.
> *--------------------------------------------------------
> xorit section.
> x000.
>
> CALL "CBL_XOR"
> USING encryption-key
> eb-string
> BY VALUE xor-len
> RETURNING xor-return-code
> END-CALL
> if xor-return-code = zero
> set eb-ok to TRUE
> else
> set eb-bad-char to TRUE
> end-if
> .
> x999.
> exit.
> *--------------------------------------------------------
> asc2hex section.
> ah000.
> move eb-string to work-string
> move spaces to eb-string
> perform
> varying ws-x1
> from 1
> by 1
> until ws-x1 > xor-len
> move low-values to ws-byte-stuff
> move ws-char (ws-x1) to lod-byte
> divide 16 into ws-binary
> giving quotient
> remainder rem
> add 1 to quotient
> add 1 to rem
> move hex-values (quotient) to hod-hex
> move hex-values (rem) to lod-hex
> string
> eb-string
> delimited by space
> two-bytes
> delimited by size
> into eb-string
> end-string
> end-perform
> .
> ah999.
> exit.
>
> *--------------------------------------------------------
> hex2asc section.
> ha000.
> move eb-string to work-string
> move spaces to eb-string
> perform
> varying ws-x1
> from 1
> by 1
> until ws-x1 > xor-len
> move low-values to ws-byte-stuff
> set hv-x1 to 1
> search hex-values
> at end set eb-bad-char to true
> go to ha999
> when hex-values (hv-x1) = ws-char (ws-x1)
> set num to hv-x1
> subtract 1 from num
> multiply num by 16 giving ws-binary
> end-search
> set ws-x1 up by 1
> set hv-x1 to 1
> search hex-values
> at end set eb-bad-char to true
> go to ha999
> when hex-values (hv-x1) = ws-char (ws-x1)
> set num to hv-x1
> subtract 1 from num
> add num to ws-binary
> end-search
> string
> eb-string
> delimited by space
> lod-byte
> delimited by size
> into eb-string
> end-string
> end-perform
> divide xor-len by 2 giving xor-len
> .
> ha999.
> exit.
>
>
> *---------------- END OF PROGRAM 'HERAcrpt' ----------------
>
>
>
> > Thanks,
> > Vik
>
> You're welcome...
>
> Pete.
>
>

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