Hi,

I'm testing to use the encryption feature of inno (5.0.5) and notice there
is no mentioning of it in the "Compile Script" log windows, also the
filesize is basicly the same 1731kb w/o changes to 1732kb with encryption
and a 14 chars password. I just wonder if this is "normal" as I expected
the filesize to increase a bit more?

Just using the password and no encryption doesn't change filesize as all,
btw.

/joakim

From:	Andrew Fiddian-Green
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 13:41:57 +0100

> .. I expected the filesize to increase a bit more?

Generally encrytion hardly increases the file size. A stream cipher
transforms produces one output byte for every input byte (so there is zero
increase in size). On the othe hand a block cipher breaks the input file
into blocks and creates one output block for every input block, (so in the
worst case your output file will be one block larger).

Regards,
AndrewFG

"Joakim" wrote in message
news:ca75f616f47f131f9e874e89f5cda1e6$1@news.jrsoftware.org...
> Hi,
>
> I'm testing to use the encryption feature of inno (5.0.5) and notice there
> is no mentioning of it in the "Compile Script" log windows, also the
> filesize is basicly the same 1731kb w/o changes to 1732kb with encryption
> and a 14 chars password. I just wonder if this is "normal" as I expected
> the filesize to increase a bit more?
>
> Just using the password and no encryption doesn't change filesize as all,
> btw.
>
> /joakim
>

From:	Joakim
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 16:05:38 +0000 (UTC)

Ok thanks for that enlightenment :-)

/joakim
Andrew Fiddian-Green wrote:

>> .. I expected the filesize to increase a bit more?
>
> Generally encrytion hardly increases the file size. A stream cipher
> transforms produces one output byte for every input byte (so there is zero
> increase in size). On the othe hand a block cipher breaks the input file
> into blocks and creates one output block for every input block, (so in the
> worst case your output file will be one block larger).
>
> Regards,
> AndrewFG
>
>
> "Joakim" wrote in message
> news:ca75f616f47f131f9e874e89f5cda1e6$1@news.jrsoftware.org...
>> Hi,
>>
>> I'm testing to use the encryption feature of inno (5.0.5) and notice there
>> is no mentioning of it in the "Compile Script" log windows, also the
>> filesize is basicly the same 1731kb w/o changes to 1732kb with encryption
>> and a 14 chars password. I just wonder if this is "normal" as I expected
>> the filesize to increase a bit more?
>>
>> Just using the password and no encryption doesn't change filesize as all,
>> btw.
>>
>> /joakim
>>

From:	Martijn Laan
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 13:46:53 +0100

Hi,

Joakim wrote:
> I'm testing to use the encryption feature of inno (5.0.5) and notice
> there is no mentioning of it in the "Compile Script" log windows

Acually it mentions it twice, once about reading iscrypt.dll and once
about the encryption initialization.

Greetings,
Martijn Laan
--
// Live Good. Do Right. Ride Hard.
//
// Inno Setup QuickStart Pack: http://www.jrsoftware.org/isdl.php#qsp
// My Inno Setup Extensions: http://isx.wintax.nl

From:	Joakim
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 16:10:17 +0000 (UTC)

Ok now I see it, archive have almost 600 files so I missed it inbetween
before. Sorry and thanks anyway.

/joakim

Martijn Laan wrote:

> Hi,
>
> Joakim wrote:
>> I'm testing to use the encryption feature of inno (5.0.5) and notice
>> there is no mentioning of it in the "Compile Script" log windows
>
> Acually it mentions it twice, once about reading iscrypt.dll and once
> about the encryption initialization.
>
> Greetings,
> Martijn Laan
> --
> // Live Good. Do Right. Ride Hard.
> //
> // Inno Setup QuickStart Pack: http://www.jrsoftware.org/isdl.php#qsp
> // My Inno Setup Extensions: http://isx.wintax.nl

From:	Joakim
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 16:12:01 +0000 (UTC)

Btw, a followup question. Is it only the files in [Files] getting
encrypted, what about the [code] section, is it wide open for preying eys?

/joakim
Martijn Laan wrote:

> Hi,
>
> Joakim wrote:
>> I'm testing to use the encryption feature of inno (5.0.5) and notice
>> there is no mentioning of it in the "Compile Script" log windows
>
> Acually it mentions it twice, once about reading iscrypt.dll and once
> about the encryption initialization.
>
> Greetings,
> Martijn Laan
> --
> // Live Good. Do Right. Ride Hard.
> //
> // Inno Setup QuickStart Pack: http://www.jrsoftware.org/isdl.php#qsp
> // My Inno Setup Extensions: http://isx.wintax.nl

From:	Martijn Laan
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 17:22:38 +0100

Hi,

Joakim wrote:
> Btw, a followup question. Is it only the files in [Files] getting
> encrypted, what about the [code] section, is it wide open for preying eys?

It's stored as ROPS bytecode but no, it isn't encrypted. Encryption is
not possible for the [Code] section since Setup needs it to run. This
applies to all sections BTW and not just [Code].

Greetings,
Martijn Laan--
// Live Good. Do Right. Ride Hard.
//
// Inno Setup QuickStart Pack: http://www.jrsoftware.org/isdl.php#qsp
// My Inno Setup Extensions: http://isx.wintax.nl

From:	Joakim
Subject:	Re: Encryption filesize
Date:	Tue, 21 Dec 2004 17:08:37 +0000 (UTC)

So if I have got this right, it's only the compressed files as such that
got encrypted, NOT the [Files] section as such?

/joakim

Martijn Laan wrote:

> Hi,
>
> Joakim wrote:
>> Btw, a followup question. Is it only the files in [Files] getting
>> encrypted, what about the [code] section, is it wide open for preying eys?
>
> It's stored as ROPS bytecode but no, it isn't encrypted. Encryption is
> not possible for the [Code] section since Setup needs it to run. This
> applies to all sections BTW and not just [Code].
>
> Greetings,
> Martijn Laan--
> // Live Good. Do Right. Ride Hard.
> //
> // Inno Setup QuickStart Pack: http://www.jrsoftware.org/isdl.php#qsp
> // My Inno Setup Extensions: http://isx.wintax.nl

From:	Martijn Laan
Subject:	Re: Encryption filesize
Date:	Wed, 22 Dec 2004 00:05:02 +0000 (UTC)

Hi,

Joakim wrote:
> So if I have got this right, it's only the compressed files as such that
> got encrypted

Yes.

Greetings,
Martijn Laan

From:	Gavin Lambert
Subject:	Re: Encryption filesize
Date:	Wed, 22 Dec 2004 13:33:32 +1300

Martijn Laan wrote:
> It's stored as ROPS bytecode but no, it isn't encrypted. Encryption is
> not possible for the [Code] section since Setup needs it to run. This
> applies to all sections BTW and not just [Code].

Here's a crazy thought: would it be possible to create *two* code
sections (one [Code] and one [EncryptedCode])?

Obviously certain routines (InitializeSetup, InitializeWizard, probably
DeinitializeSetup too, and some uses of {code:...}) would need to be in
the unencrypted section, but if you made sure that Check functions and
CurStepChanged weren't called until after the password was entered, then
those could live in the [EncryptedCode] section. CurPageChanged... I
guess that would have to be unencrypted, but you'd be able to have
encrypted OnActivate handlers (for all except wpWelcome and wpPassword,
anyway!) :)

The problem, of course, is that the encrypted code needs to "know" about
the unencrypted code (so that it can use its global variables, and call
its routines). The reverse must be forbidden. I'm not sure whether
ROPS can do that.

Of course, this is all just "wouldn't it be cool if..."-category stuff,
not "I really want it!"-category stuff -- the only reason I could think
of for wanting to do this in practice would be for security -- and
security is probably better off being in your app anyway. I just get
carried away with amusing ideas sometimes ;)

(For that matter, [Files]/[Registry]/[Components] etc could probably get
encrypted too, if their respective wizard pages weren't filled in until
after wpPassword. But only if the setup author was expecting that!)