Re: Decrypt with QC3DECDT

[Jon Paris <jon.paris@xxxxxxxxxxxxxx>]

I think the answer is in the category of "Dr. It hurts when I bang my head against a wall." - don't do the trim.  Use %Len against the varying field directly (not the trimmed version) so that you get the right length. 


On 2013-11-21, at 12:05 PM, Jon S <rvrratjon@xxxxxxxxxxx> wrote:

> Looking at the encrypted field, it appears that all are 16 characters except the ones that kicked out in error which are only 15 so it appears that the last space is a valid blank character but I am only passing in 15 via the %len(%Trimr(argData) or %size(argData) causing it to error out. I am not sure how to handle that. Any suggestions? Below is the prototype for DecryptDataAPI
>
> D decryptDataAPI...
> D                 PR                  extPgm('QC3DECDT')
> D  argIn                     65535    const options(*varsize)
> D  argInLen                     10I 0 const
> D  argAlg                    65535    const options(*varsize)
> D  argAlgFmt                     8    const
> D  argKey                    65535    const options(*varsize)
> D  argKeyFmt                     8    const
> D  argCryptoPro                  1    const
> D  argCryptoDev                 10    const
> D  argOut                    65535
> D  argOutBuffLen                10I 0 const
> D  argOutLen                    10I 0
> D  argError                           likeDs(QUSEC)
>
>
>
> > Subject: Re: Decrypt with QC3DECDT
> > From: jon.paris@xxxxxxxxxxxxxx
> > Date: Thu, 21 Nov 2013 11:21:22 -0500
> > To: rpg400-l@xxxxxxxxxxxx
> >
> > argData is a varying length field - so trim should be done on loading - doing it on the call is asking for trouble. Not sure what the compressed string looks like - but for sure it could have a valid space at the end. Also you haven't shown the Pr for decryptDataAPI so I can't tell if that is having an effect. The parm is not a varying field that is for sure.
> >
> > On 2013-11-21, at 10:22 AM, Jon S <rvrratjon@xxxxxxxxxxx> wrote:
> >
> > > This is strange. When I encrypt the 6 character string, it returns the length as 16 for the encrypted length but when I turn around and try to decrypt it the program shows that the length of the encrypted string to be only 15. Maybe the %trimr on the %len(%Trimr(argData)) for the encrypted string is causing me the problem? 
> > >
> > > > From: rvrratjon@xxxxxxxxxxx
> > > > To: rpg400-l@xxxxxxxxxxxx
> > > > Subject: RE: Decrypt with QC3DECDT
> > > > Date: Thu, 21 Nov 2013 09:11:29 -0600
> > > >
> > > > Looking at it again, the clear data length is set to 65535 and the original unencrypted field was only 6 bytes.
> > > >
> > > > decryptData...
> > > >               B                   EXPORT
> > > > decryptData...
> > > >               PI         65535A
> > > > argData                   65535A   const varying
> > > >                                   options(*varsize)
> > > > argInLen                     10I 0
> > > >
> > > > svOutData       S          65535A
> > > >
> > > > D svOutDataLen    S             10I 0
> > > > D Len             S             10I 0
> > > > D svBytes         S             52A
> > > > /free
> > > >  svOutData = *BLANKS;
> > > >  len = %size(svOutData);
> > > >  len = %len(%Trim(argData));
> > > >  // API
> > > >  decryptDataAPI(argData: ):
> > > >              QC3D0200: 'ALGD0200':
> > > >              keyDesc: 'KEYD0200':
> > > >              cryptoPro: cryptoDev:
> > > >              svOutData: %size(svOutData): svOutDataLen:
> > > >              stdError);
> > > >
> > > >
> > > >
> > > > > Subject: Re: Decrypt with QC3DECDT
> > > > > From: jon.paris@xxxxxxxxxxxxxx
> > > > > Date: Thu, 21 Nov 2013 10:02:33 -0500
> > > > > To: rpg400-l@xxxxxxxxxxxx
> > > > >
> > > > > Well there are probably circumstances where 16 bytes may well expand to more than 50. Assuming that normal compression techniques are in play then (say) 60 blanks if included in the encrypted string would probably compress down to 3 or 4 bytes.
> > > > >
> > > > > Why not make the field bigger and see what you get?
> > > > >
> > > > >
> > > > > On 2013-11-21, at 9:50 AM, Jon S <rvrratjon@xxxxxxxxxxx> wrote:
> > > > >
> > > > > > I am trying to use QC3DECDT to decrypt an encrypted field which was also encrypted with QC3DECDT. Sometimes (6 out of 2381 records ) I am getting CPF9DD6 which is "Length of area provided for output data is too small.". I have my clear data output length set to 50 which should be plenty big, as the first one I am getting an error on is only 16 characters encrypted. Can anyone help?
> > > > > >
> > > > > > Thanks, Jon
> > > > > > 		 	   		  
> > > > > > -- 
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> > > > > Jon Paris
> > > > >
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> > > > >
> > > > >
> > > > >
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> > Jon Paris
> >
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> >
> >
> >
> >
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> 		 	   		  
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Jon Paris

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