Encrypting a field

markg30 · Aug 2, 2000

I am running FPD 2.6 and I need to be able to encrypt/decrypt certain fields in a database at runtime using DES encrytion.  Does anyone know of a PLB or BIN to allow me to do this?  I have downloaded 3rd party DES encrytion libraries for C and tries to use them in my own PLB using the FoxPro LCK, but the encrytion functions crash FoxPro when then are called. Thanks

dgrewe · Aug 3, 2000

Will these 2 function help?  they only work on strings so you will have to convert other field types to a string before playing with it. */*************************************************************************** */Program   : function CODEIN */System    : */Purpose   : Scrambles a string into an unreadable form */Syntax    : = CodeIn(Str,CodeSeed) */Returns   : String */Parameter : String - Str - The String to Be Scrambled */          : Integer - Seed - Number to offset the asc code by */Defaults  : None */Requires  : None */Changes   : Nothing */Internal Calls : None */External Calls : None */Version   : 1.0 */Dated     : 02/03/1989 */Written By: David W. Grewe */*************************************************************************** *& Utility - Security */*************************************************************************** */ Record Of Change */ */*************************************************************************** parameters P_STR, P_SEED private P_STR, P_SEED private L_PARA, L_LEN, L_CODEIN, L_PLACE L_PARA = parameters() do case case L_PARA < 1 .or. type('P_Str') # 'C'   wait window "Function L_CodeIn, Needs To Be Passes A String To Code"   return " " case L_PARA < 2 .or. type('P_Seed') # "N"   P_SEED = 10 endcase ******* P_SEED = iif(P_SEED > 20, 17, P_SEED) + 95 P_STR = trim(P_STR) L_LEN = len(P_STR) L_CODEIN = '' ******* ***  encryption routine ******* for I = 1 to L_LEN   L_PLACE = asc(substr(P_STR,I,1)) + P_SEED - I   L_CODEIN = L_CODEIN + chr(L_PLACE) endfor ****** release P_STR, P_SEED, L_PARA, L_LEN, L_PLACE return L_CODEIN */*************************************************************************** */Program   : function CODEOUT */System    : */Purpose   : Unscrambles A string, Scrambled with Function CodeIn, */          : back to a readable form */Syntax    : = CodeOut(Str,Seed) */Returns   : String */Parameter : String - Str - The String to Be UnScrambled */          : Integer - Seed - Number To Offset The AscCode By(must be the same as Codein) */Defaults  : None */Requires  : None */Changes   : Nothing */Internal Calls : None */External Calls : None */Calls     : */Version   : 1.0 */Dated     : 02/03/1989 */Written By: David W. Grewe */*************************************************************************** *& Utility - Security */*************************************************************************** */ Record Of Change */ */*************************************************************************** parameters P_STR, P_SEED private all like P_*, L_* L_PARA = parameters() do case case L_PARA < 1 .or. type("P_Str&quot

# "C"   wait window "Function L_CodeOut, Needs To Be Passes A String To UnCode"   return " " case L_PARA < 2 .or. type("P_Seed&quot

# "N"   P_SEED = 10 endcase P_SEED = iif(P_SEED > 20, 17, P_SEED) + 95 P_STR = trim(P_STR) L_LEN = len(P_STR) L_CODEOUT = "" ********************* ***  decoding routine ********************* for I = 1 to L_LEN   L_PLACE = asc(substr(P_STR,I,1)) - P_SEED + I   if L_PLACE < 32 .or. L_PLACE > 128     wait window "The string was not Scrambled with Function CodeIn"     return " "   else     L_CODEOUT = L_CODEOUT + chr(L_PLACE)   endif endfor ****** return L_CODEOUT here is a sample routine on using them  The VARMEM.DAT is just a dbf renamed and the VARMEM.DIF is a IDX renamed.  Figured if the person breaking into the system knew it used DBF's and CDX's the DAT and DIF would help delay the action */*************************************************************************** */Program   : Function varaccs */System    : */Purpose   : Fills / changes the F_ variables passed to it from the information in the Network Database */Syntax    : Do UserFind */Returns   : Nothing */Parameter : Nothing */Default   : Nothing */Requires  : A Database Named Network and the uc* Memvars previously declaired public */Calls     : */Version   : 1.0 */Dated     : 02/04/1989 */Written By: David W. Grewe */*************************************************************************** *& Utility-Security */*************************************************************************** */ Record Of Change */ */*************************************************************************** parameters P_NetName if parameters() # 1  P_Netname = ucNetName endif *********************** on error quit L_Alias = alias() if used("VARMEM&quot

select VARMEM else  select 0  use VARMEM.DAT alias VARMEM endif set index to VARMEM.DIF * * Get the new user information * set exact on P_NetName = codein(P_NetName) Seek P_NetName L_passback = .f. if found()  ucNetName  = alltrim(codeout(VARMEM.ID))  ucPassWord = alltrim(codeout(VARMEM.FILE))  unSecurity = val(codeout(VARMEM.TYPE))  ucDrive    = iif(codeout(VARMEM.DRIVE) = " ", "C", codeout(VARMEM.DRIVE))+ ":"  ucPerson   = substr(codeout(VARMEM.NAME), 1, at(" ",codeout(VARMEM.NAME))-1)  ucTitle    = alltrim(codeout(VARMEM.TITLE))  F_Pdriver  = alltrim(codeout(VARMEM.PRINTER))  L_passback = .t. endif set exact off use do errcall if ! empty(L_Alias)  select (L_Alias) endif return l_passback David W. Grewe <a href=mailto

ave@internationalbid.net>Dave@internationalbid.net</a> <a href= > </a>

markg30 · Aug 3, 2000

While I would think that would be good enough, my client insists on DES3 or equivalent encrytion.  Any thoughts?

dgrewe · Aug 3, 2000

Sorry, Everything I've read on DES is file encryption.  Have not seen anything on placing segments of a DES file inside another file.  However I guess an encrypted file can be stored in a general field. What file did you download and from where ? David W. Grewe <a href=mailto

ave@internationalbid.net>Dave@internationalbid.net</a> <a href= > </a>

markg30 · Aug 3, 2000

Actually, I just need to encrypt fields.  for example, I need a foxpro function such as en_text=ENCRYPT(param1, param2) (or DECRYPT) where param1 is a key and param2 is the text string I want to encrypt.  The only stipulation is that the encryption needs to be DES. We are a telemarketing company, and one of our clients wants to provide us to encrypt credit card numbers so that casually browsing a database will not allow you to deciper these numbers with calling the DECRYPT function on with the key and the scrambled field as parameters. I have downloaded various snippets of DES C code from various places, but most of them were written for UNIX systems and are parts of larger applications; it's been a royal pain trying to get the code to compile into a FoxPro PLB...  I was hoping maybe someone had already done this for me.

ANEIMANIS · Jan 27, 2001

THERE IS A SIMPLE WAY TO DO THE JOB,

*FUNCTION ENCRYPT
PARAMETER WHATTODO, THEFIELD
* WHATTODO = 1 -> ENCRYPT
* WHATTODO = 2 -> UN-ENCRYPT
* THEFIELD = TEXT TO BE HANDLE

DO CASE
CASE WHATTODO=1
THEFIELD=CHRTRAN(THEFIELD,'ABC...','"#$%&...')
* PUT IN ALL CHARACTERS
* YOU NEED TO ENCRYPT
CASE WHATTODO=2
THEFIELD=CHRTRAN(THEFIELD,'"#$%&...','ABC...')
* PUT IN ALL CHARACTERS
* YOU NEED UN-ENCRYPT
ENDCASE
RETURN(THEFIELD)

* NOTE THAT ALL YOU ARE DOING IS TRANSFORMING EACH CHARACTER INTO OTHER, THIS WAY OF ENCRYTION IS NOT THE MORE SAFELY BUT IT IS FAST AND WORKS GOOD ACCORDING YOUR NEEDS.

ANEIMANIS@HOTMAIL.COM

infinitelo · Mar 11, 2001

have you tried to save the data you want to encrypt to a file then run you c program on the file instead of local mem var? then you can simply append the field from the encrypted file. the c program might try to run wild as a call but it prob wont as an external run.

Maricus · Mar 14, 2001

I have also looking for the same program that Infinitelo wants. I recently bumped into and downloaded some utilities, only that they are shareware. Since I did not have the money then, I held. Should you be interest, I can upload or send direct.

Maricus

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Encrypting a field

markg30

Programmer

dgrewe

MIS

markg30

Programmer

dgrewe

MIS

markg30

Programmer

ANEIMANIS

Technical User

infinitelo

Programmer

Maricus

Programmer

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