Re: [Firebird-devel] RFC: Adding a cryptographic library for use in firebird

[Adriano d. S. F. <adr...@uo...>]

Mark O'Donohue wrote:
> b) For encrypt(x) it is easy, the return type is based on input type,
> so text returns text (although unsigned char, charset none, but could
> be octets), and blob returns blob.
>   
I think octets is more correct.

> And as you said, the return type for text is varchar : length =
> len(arg[2]) + maxblocksize.  The actual eval call will return a string
> of up to that length.
>
>
> c) In makeEncrypt to build the result I currently have :
>
>    const dsc* value = args[2];
>
>     if (value->isBlob()) {
>                // make  blob return type
> 	}
>    else (value->isText())
> 	{
>                // make varchar return type  len(value) + maxblocksize.
> 	}
>     else {
>           ?? now what best to do here, throw an exception?
>    }
>   
See makeRevert:
    if (value->isBlob())
        *result = *value;
    else
        result->makeVarying(value->getStringLength(), value->getTextType());


>
> d) Opps, I had a empty function for setParamsEncrypt() lets rectify that now.
>
>      setParamsEncrypt() presumably checks the input parameters,   I
> need parameters
>              1) cypher: [text,
>              2) key  : text,
>              3  data : blob|text
>
>      now from other instances of setXXX  all I see are:
>
> 	if (argsCount >= 1 && args[0]->isUnknown())
> 		args[0]->makeText(GUID_BODY_SIZE, ttype_ascii);
>
> So is this only handling unknown types?, and whats best to do for the
> three parameters I have (do I need to invent a max size for cypherName
> and key,  can I declare them as varying (there is no sample like that
> in all the other functions)?, and what about arg[2] do I just check
> its unknown, or can I enforce its blob|text here?
>
> btw: one wonders if it was an ex-pascal programmer who did :
>                               if (argsCount >= 1 && args[0]->isUnknown()) :-).
>   
isUnknow() means a parameter (question mark). And this is where dynamic 
varchar length for parameters go.

Current, things like this does not work: revert(?)
But this works: revert(cast(? as varchar(10)))

If this is the cast you are talking, it's ok for now.

>
>   
>> On v3, we could have variable (dynamic) length parameters and output values.
>>
>>     
>
> Maybe I need to look at that, can you give a brief overview, or point
> me to something ?
There is nothing proposed yet. Just some discussions of things that we 
need to extend on SQLDA/VAR.


Adriano