Re: DBMS_CRYPTO Error

Morning Ken,

On 23/04/12 20:54, Norman Dunbar wrote:
> I'm not 100% sure as I'm away from my desk at present, but I think when
> I used DES3 a few years ago, I needed to pad the text to be encrypted to
> a multiple of some length. I'll check tomorrow.

I'm in the office and I've checked my code. It is true, the data to be 
encrypted needs to be a multiple of 8 characters long. As per this from 
my code's package body:

function encrypt(iString in blob) return blob
as
        vData raw(1024);
        vBlob blob;

begin
        -- Extract raw data, pad it out &  encrypt it
        vData := BlobToRaw(iBlob => iString,
                        iPad => true);

        vData := dbms_obfuscation_toolkit.DESEncrypt(...);


The BlobToRaw code is this:


function BlobToRaw(iBlob in blob, iPad in boolean := true)
as
        vRaw raw(1024;
        vLength number;
        vPad integer
        ...
begin
        vLength := dbms_lob.GetLength(iBlob);
        if (vLength <> 0) then
                -- Read blob into raw
                ...
        end if;

        -- Pad if required
        if (iPad) then
                vPad := 8 - mod(vLength, 8);
                if (vPad <> 0) then
                vRaw := utl_raw.concat(vRaw,
                                utl_raw.cast_to_raw(rpad(chr(0),
                                                        vPad,
                                                        chr(0))
                                )
                        );
                end if;
        end if;
...

I remember reading somewhere that the data has to be an exact multiple 
of 8 characters long. In the docs for dbms_obfuscation_toolkit for 9i I 
think.

I also note that I seem to have used the iPad name long before Apple, 
wonder if I can sue!  ;-)

By the way, this was part of a password vault system I had to write many 
many years ago, all my data are well short of the 1024 characters I'm 
using for the RAWs above.


HTH

Cheers,
Norm.

-- 
Norman Dunbar
Dunbar IT Consultants Ltd

Registered address:
Thorpe House
61 Richardshaw Lane
Pudsey
West Yorkshire
United Kingdom
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Company Number: 05132767
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