<i><font color="#663300">
OTHERWISE
llRetVal = This.EncryptionRoutine(tcString, "ENCRYPT", /at/ tcEncryptedString)
</font></i>
Greetings Graeme,
The encryption used here is interesting, but hardly difficult to break .D.OT
I think you should have the code if only to feel complete.
I am pretty sure that the intent was to allow each devleoper to
substitute another encryption method here, as desired.
May I suggest looking for CIPHER50.ZIP in a public library?
Here is the code from .encryptionroutine:
************************************************************
* Method: String.EncryptionRoutine() - DATA.VCX
*
*) Description:
*) This method encrypts and decrypts character strings
*
* Parameters:
* <expC1> - the string to encrypt or decrypt
* <expC2> - the desired action ["ENCRYPT"|"DECRYPT"]
*
*@ Inputs: None
* Outputs: None
*$ Usage:
*$ <objectname>.EncryptionRoutine( <expC1> , <expC2> )
*
*â0 Example:
*â0 THIS.EncryptionRoutine("Catmandu","ENCRYPT") - encrypts
*â0 THIS.EncryptionRoutine("AMD9mlkd","DECRYPT") - decrypts
*
* Returns: CHARACTER - encrypted/decrypted character string.
*
* Invariants
* 1. Pre-Condition:
* a. The desired action is a valid request
* b. The first parameter is a string
*
* 2. Post-Condition
* a. If ENCRYPTING the string returned is encrypted
* b. If DECRYPTING the string returned is readable
*
*
*? Notes: None
* Local Routines: None
*-- Process:
*-- 1. Determine the length of the string
*-- 2. FOR the length of the passed string
*-- 3. DO CASE
*-- 4. CASE Encrypting
*-- 5. Encrypt the digit equal to the count of the FOR loop
*-- 6. CASE Decrypting
*-- 7. Decrypt the digit equal to the count of the FOR loop
*-- 8. ENDCASE
*-- ENDFOR
*
* Change Log:
* CREATED Tuesday, 03/19/96 20:53:39 - CTB:
************************************************************
LPARAMETERS pc_string, pc_func, pc_encryptedstring
LOCAL lc_estr, ln_long, ln_pos
*°°°°°°°°°°°°°°°°°°°° MEMORY VARIABLE DEFINITIONS °°°°°°°°°°°°°°°°°°°°°°
*° lc_estr - Encrypted string °
*° ln_long - Length of character string passed °
*° ln_pos - Character position °
*°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°°
lc_estr = ""
*--------------------------------------------------
*-- Determine the length of the character string
*--------------------------------------------------
ln_long = LEN(pc_string)
*--------------------------------------
*-- For the length of the entire string
*--------------------------------------
FOR ln_pos = 1 TO ln_long
DO CASE
CASE pc_func = 'ENCRYPT'
*---------------------
*-- Encrypt the string
*---------------------
lc_estr = lc_estr + CHR(ASC(SUBSTR(pc_string,ln_pos,1)) + ;
ln_pos + ln_long)
CASE pc_func = 'DECRYPT'
*---------------------
*-- Decrypt the string
*---------------------
lc_estr = lc_estr + CHR(ASC(SUBSTR(pc_string,ln_pos,1)) - ;
ln_pos-ln_long)
ENDCASE
ENDFOR (ln_pos)
pc_encryptedstring = lc_estr
RETURN IIF(EMPTY(lc_estr),.F.,.T.)
*--------------------------------
* EOM: String::EncryptionRoutine()
*--------------------------------
James Sayer
©2001 James Sayer |
