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Encrypted storage with streaming (OpenSSL, AES) [message #23087] Wed, 16 September 2009 22:17 Go to next message
Mindtraveller is currently offline  Mindtraveller
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Registered: August 2007
Location: Russia, Moscow rgn.
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Sometimes we may have task to store some large file (4+ GB) or small string inside encrypted storage. I tried to make a pair classes which make it easy. This is the first version, so any ideas are welcome.

This package assumes you have OpenSSL library successfully installed and its paths are added to TheIDE.

OK, let me introduce a pair of classes called AESEncoderStream and AESDecoderStream. They support streamed adding and encryption/decryption of data. Encryption is made with AES (Rijndael) with 128, 192 or 256 bit keys.

Encrypted data 32 bytes larger than source length aligned to 16-byte boundary. I.e. if your source data is 170 bytes long, the resulting length is:
170 rounded by 16-byte pieces = 176
plus
32 (header data)
= 176 + 32 = 208 bytes.
Not so ugly for a number of applications especially if source data is large.

Here is a simple self-explanating demo:
#include <Core/Core.h>
#include <openssl/aes.h>
#include <AESStream/AESStream.h>

using namespace Upp;

CONSOLE_APP_MAIN
{
	AESInit();

	// Generate cryptographically stable key
	String key(AESRandomString(32));

	// Encryption
	String sIn,sOut;
	sIn = "qwertyuiop[p\tasdfghjkl;zxcvbnm,./quwiueqiwueoiquweioquweioquweiqwueicuwinuqiweqiwue	pqiueci	eiqniuriryuweyruweyruewrycuwbrurbywuyrwquiercbbcrebrquwey";
	AESEncoderStream aesEncoder(sIn.GetLength(), key);
	aesEncoder << sIn.Left(10);
	aesEncoder << sIn.Mid(10,10);
	aesEncoder << sIn.Right(sIn.GetLength() - 20);

	sOut << aesEncoder; //do streamed encoding
	
	// Decryption
	//key.Set(0, 'a'); //uncomment to see what happens with wrong key
	AESDecoderStream aesDecoder(key);
	
	aesDecoder << sOut.Left(15); //you may add by parts
	aesDecoder << sOut.Right(sOut.GetLength() - 15);
	
	try
	{
		String sDecoded;
		sDecoded << aesDecoder; //throw exception if key is wrong
		
		Cout() << (sDecoded == sIn) << "\n\n"; //check if all converted successfully
	}
	catch (const char *xp)
	{
		Cout() << "\n!!Error: " << ToSystemCharset(xp);
	}
}

[Updated on: Fri, 18 September 2009 11:16]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #23103 is a reply to message #23087] Thu, 17 September 2009 09:34 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

How are you installed OpenSSL in Windows ?

I have seen an installer in here http://www.slproweb.com/products/Win32OpenSSL.html but I would like to know your opinion.

Best regards
Koldo


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23120 is a reply to message #23103] Thu, 17 September 2009 19:57 Go to previous messageGo to next message
Weras is currently offline  Weras
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Registered: August 2009
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Hi koldo!

I had resolved this problem and I did so.
1. Download openssl-0.9.8k.tar.gz from
https://www.openssl.org/source/
2. Unpack archive to C:\temp\openssl-0.9.8g
3. Download and install ActivePerl
4. Now type in the command line:
1) C:\temp\openssl-0.9.8g>perl Configure VC-WIN32 --prefix=c:/temp/openssl-bin/
2) C:\temp\openssl-0.9.8g>%comspec% /k ""c:\Program Files\Microsoft Visual Studio 8\VC\vcvarsall.bat"" x86
3) C:\temp\openssl-0.9.8g>ms\do_masm.bat
4) if you need static library write
C:\temp\openssl-0.9.8g>nmake -f ms\nt.mak
else, if you need dynamic library write
C:\temp\openssl-0.9.8g>nmake -f ms\ntdll.mak
5. The result is files*.lib & *.dll and include directory
6. Add .../openssl/inc32 as Include and .../openssl as Linker directories

Is enough to work with openssl

[Updated on: Thu, 17 September 2009 20:05]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #23130 is a reply to message #23120] Thu, 17 September 2009 22:55 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Weras and Mindtraveller

Just excellent.

The Weras instructions worked perfectly the first time Smile.
Sorry to say that it is unusual.

And Mindtraveller wrapper and demo worked well the first time Very Happy .

Function dword rdtsc() uncludes a little of assembler so it only compiles with MSC. I will try to translate it to Gcc to see if it works with MinGW and Linux.

Best regards
Koldo


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23139 is a reply to message #23130] Fri, 18 September 2009 11:20 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Hi, koldo!

It was Weras who instructed me how to install OpenSSL so I asked him to answer yur question.

Thanks for trying Linux version, it's a great effort.
I have just found a pair of small bugs and reuploaded sources. If you wish to try AESStream, pleas rewrite sources with new versions. If you manage to make POSIX version of rdtsc - it would be great too (I'm no professional in GCC-accepted assembler).

I wonder if people need this too. If it is so, someone from authors may upload AESStream to official Bazaar.
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23143 is a reply to message #23139] Fri, 18 September 2009 12:28 Go to previous messageGo to next message
tojocky is currently offline  tojocky
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Mindtraveller wrote on Fri, 18 September 2009 12:20

Hi, koldo!

It was Weras who instructed me how to install OpenSSL so I asked him to answer yur question.

Thanks for trying Linux version, it's a great effort.
I have just found a pair of small bugs and reuploaded sources. If you wish to try AESStream, pleas rewrite sources with new versions. If you manage to make POSIX version of rdtsc - it would be great too (I'm no professional in GCC-accepted assembler).

I wonder if people need this too. If it is so, someone from authors may upload AESStream to official Bazaar.


Very nice package and wiki how to build openssl on win32.
Thank you!

Ion Lupascu (tojocky)
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23144 is a reply to message #23087] Fri, 18 September 2009 13:23 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

About rdtsc, in fact it compiles in gcc as it has an ifdef so that:

- If MSC, it takes a value from rdtsc (time stamp counter 64-bit register)
- Else it takes Random()

It seems that to get a random number our Random() implementation is better than the clock (MT19937 algorithm), so perhaps rdtsc() would have to be changed with Random()

I have tried to compile in MinGW, but I get linking errors, in summary:

Openssl\out32\libeay32.lib(tmp32/ui_openssl.obj),(.text[_rea d_string_inner]+0xb): undefined reference to `__security_cookie'
Openssl\out32\libeay32.lib(tmp32/ui_openssl.obj),(.text[_rea d_string_inner]+0x149): undefined reference to `@__security_check_cookie@4'
Openssl\out32\libeay32.lib(tmp32/ecp_smpl.obj),(.text[_ec_GF p_simple_group_set_curve]+0x6): undefined reference to `_chkstk'

Does anybody know how to solve these problems with chkstk and security_cookie ?

Best regards
Koldo


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23145 is a reply to message #23144] Fri, 18 September 2009 14:01 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Yes, I tried it too and had the same problems.
Currently had no time to discover this (actually MSC9 satisfies me on Win32), but some googling could help.

UPDATE: this link might be useful
http://wagner.pp.ru/~vitus/articles/openssl-mingw.html

[Updated on: Fri, 18 September 2009 14:09]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #23150 is a reply to message #23087] Fri, 18 September 2009 23:01 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

Thank you for your reference.

Unfortunately it has been impossible for me to compile it directly, with MSys or with Cygwin.
In any case sooner or later I get an error that finish the process. Sad

Best regards
Koldo


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #23175 is a reply to message #23150] Wed, 23 September 2009 03:29 Go to previous messageGo to next message
kasome is currently offline  kasome
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Great job. Surprised

Thanks, Mindtraveller.
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25385 is a reply to message #23175] Sat, 20 February 2010 17:08 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

AESStream is not included in Bazaar yet.

I think it would be good to include it Smile


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25389 is a reply to message #25385] Sat, 20 February 2010 23:19 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Please upload it. It looks like I have no access to bazaar.

Koldo, please tell, did you try to compile this under POSIX? Did it work well or you had any problems. It would be very good to keep this solution really cross-platform (at least MSC9/Win32 + GCC/POSIX).

[Updated on: Sat, 20 February 2010 23:20]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #25391 is a reply to message #25389] Sun, 21 February 2010 08:07 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

GCC/POSIX works perfect.

MSC9/Win32 works well for me only in non DEBUG mode.

When I run WIN32 version in DEBUG mode I get a "Heap leaks detected". I get the same using the openssl .dll version.

I think the problems come from Web/SSL package, not from AESStream.


Best regards
Iñaki

[Updated on: Sun, 21 February 2010 09:09]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #25392 is a reply to message #25391] Sun, 21 February 2010 10:38 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

I have got also a "Memory leaks detected" compiling uppdev/textssl with MSC in debug mode.

Its code is just:

#include <Core/Core.h>

CONSOLE_APP_MAIN
{ 
	
}


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25394 is a reply to message #25392] Sun, 21 February 2010 12:01 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Koldo, what is the package uppdev/textssl? Never heard of that before. You mean another OpenSSL-based package?

I also changed package a bit, added tutorial (English and Russian versions), added example. Please be so kind check if it compiles (currently don't have OpenSSL installed) and upload it to bazaar.
  • Attachment: AESStream.zip
    (Size: 14.22KB, Downloaded 706 times)

[Updated on: Sun, 21 February 2010 12:08]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #25395 is a reply to message #25394] Sun, 21 February 2010 15:40 Go to previous messageGo to next message
koldo is currently offline  koldo
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Mindtraveller wrote on Sun, 21 February 2010 12:01

Koldo, what is the package uppdev/textssl? Never heard of that before. You mean another OpenSSL-based package?

I also changed package a bit, added tutorial (English and Russian versions), added example. Please be so kind check if it compiles (currently don't have OpenSSL installed) and upload it to bazaar.

Hello Mindtraveller

Web/SSL package is included in AESStream. A problem is it have memory leaks. I have found a solution to solve it, that is in Web/SSL/util.cpp:

INITBLOCK {
	Socket::Init();
	CRYPTO_set_mem_functions(SSLAlloc, SSLRealloc, SSLFree);
	SSL_load_error_strings();
	//SSL_library_init();		//SOLUTION TO MEMORY LEAK !!
}


Probably SSL_library_init(); is not necessary and as it not properly cleaned up, there are memory leaks.

To find this problem I have used uppdev/testssl package and Upp technology to detect memory leaks Smile

I have tested your changes but they do not work well Smile . Check this:

sIn includes this:
Quote:

qwertyuiop[p asdfghjkl;zxcvbnm,./quwiueqiwueoiquweioquweioquweiqwueicuwin uqiweqiwue pqiueci eiqniuriryuweyruweyruewrycuwbrurbywuyrwquiercbbcrebrquwey


sDecoded iincludes this:
Quote:

qwertyuiop[p asdfghjkl;zxcvbnm,./quwiueqiwueoiquweioquweioquweiqwueicuwin uqiweqiwue pqiueci eiqniuriryuweyruweyruewrycuwbrurbywuyrwquiercbbcrebr


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25396 is a reply to message #25395] Sun, 21 February 2010 16:01 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

MinGW works well using openssl .dll version.

Just add this to Web/SSL in "Package organizer":

index.php?t=getfile&id=2320&private=0

  • Attachment: sc.PNG
    (Size: 1.63KB, Downloaded 2368 times)


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25397 is a reply to message #25396] Sun, 21 February 2010 19:25 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

Other question. In the demo program you generate a key with AESRandomString(32).

I have integrated successfully AESStream in a program (very easy, just using your demo Smile ), but including in the program an array with the key previously generated with AESRandomString().

Is it possible to use instead an user generated key (a password) ?


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25399 is a reply to message #25397] Mon, 22 February 2010 00:48 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Hello, Koldo.

I have found bug in AESStream which led to different original and decoded strings in the example. Also I got rid of Web/SSL dependency. Just tested it, and everything seems fine.

Please try updated version of AESStream and read it's tutorial if you want to use it in your app. Tutorial say that you should not use user password instead of generated key.

Why?
1) Key must be 128/192/256 bits long. User password may have ANY length.
2) Key is very important part of cryptographic strength of overall encryption. Using criptographically weak key (user password in 99,9% of cases is extremely weak) turns all AES encryption into weak and rather breakable system. As well as using cryptographically strong key makes overall AESStream system extremely unbreakable to anyone.
  • Attachment: AESStream.zip
    (Size: 14.29KB, Downloaded 736 times)
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25401 is a reply to message #25399] Mon, 22 February 2010 07:54 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

Quote:

1) Key must be 128/192/256 bits long. User password may have ANY length.
2) Key is very important part of cryptographic strength of overall encryption. Using criptographically weak key (user password in 99,9% of cases is extremely weak) turns all AES encryption into weak and rather breakable system. As well as using cryptographically strong key makes overall AESStream system extremely unbreakable to anyone.


Does it mean that AES cannot be used for saving user files with user defined password ?

However there are programs that include this possibility with AES. For example 7zip offers AES-256 encryption http://www.7-zip.org/7z.html.

Is there a standard way to convert a 8 chars user defined password into an useful 256 AES bits key ?


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25402 is a reply to message #25401] Mon, 22 February 2010 08:31 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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koldo wrote on Mon, 22 February 2010 09:54

1) Does it mean that AES cannot be used for saving user files with user defined password ?

However there are programs that include this possibility with AES. For example 7zip offers AES-256 encryption http://www.7-zip.org/7z.html.

2) Is there a standard way to convert a 8 chars user defined password into an useful 256 AES bits key ?

1) Cryptography is no miracle, it's just math. If you use weak password, you get weak protection, and no algorithm saves you from it. This means if you want stable and strong protection, you must use stable and strong key. The one of few options here is to use key generated by OpenSSL itself.

You have to consider user password as worst type of key. Also, many passwords are too plain and dumb: 123, 111, 123456, etc. This is bad for cryptography.

Russian programmer Igor Pavlov who wrote 7zip, has chosen to use compromise solution. He takes user password, calculates SHA-256 function for it (AFAIK U++ has its realization too). Then he adds some calculations/changes to that 256-bit value and the final value is used as a key for AES encryption.

This represents fair protection, which is very much stronger than using user password as key, but at some rate weaker protection than with OpenSSL-generated key. In a number of uses it is rather good and satisfactory protection. Also it allows using protection without storing user password itself which is very good practice. But frankly speaking I haven't heard of SHA output as extremely cryptographically strong combination of bytes. This algorithm has another application field (generating unique digest "far" from original bytes).

2) AFAIK there is no "standard" way to convert user password to key. The best way is to use OpenSSL generated key. You may of course use any function like SHA-256 but you must be aware of the crytpographic strongness/weakness you give to user.

[Updated on: Mon, 22 February 2010 08:43]

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Re: Encrypted storage with streaming (OpenSSL, AES) [message #25403 is a reply to message #25402] Mon, 22 February 2010 08:50 Go to previous messageGo to next message
koldo is currently offline  koldo
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Mindtraveller wrote on Mon, 22 February 2010 08:31

koldo wrote on Mon, 22 February 2010 09:54

1) Does it mean that AES cannot be used for saving user files with user defined password ?

However there are programs that include this possibility with AES. For example 7zip offers AES-256 encryption http://www.7-zip.org/7z.html.

2) Is there a standard way to convert a 8 chars user defined password into an useful 256 AES bits key ?

1) Cryptography is no miracle, it's just math. If you use weak password, you get weak protection, and no algorithm saves you from it. This means if you want stable and strong protection, you must use stable and strong key. The one of few options here is to use key generated by OpenSSL itself.

You have to consider user password as worst type of key. Also, many passwords are too plain and dumb: 123, 111, 123456, etc. This is bad for cryptography.

Russian programmer Igor Pavlov who wrote 7zip, has chosen to use compromise solution. He takes user password, calculates SHA-256 function for it (AFAIK U++ has its realization too). Then he adds some calculations/changes to that 256-bit value and the final value is used as a key for AES encryption.

This represents fair protection, which is very much stronger than using user password as key, but at some rate weaker protection than with OpenSSL-generated key. In a number of uses it is rather good and satisfactory protection. Also it allows using protection without storing user password itself which is very good practice. But frankly speaking I haven't heard of SHA output as extremely cryptographically strong combination of bytes. This algorithm has another application field (generating unique digest "far" from original bytes).

2) AFAIK there is no "standard" way to convert user password to key. The best way is to use OpenSSL generated key. You may of course use any function like SHA-256 but you must be aware of the crytpographic strongness/weakness you give to user.


Excellent explanation Smile

I will follow your advice. Anyway, could you add a function to convert an username password into a "fair" protection ?. Thanks Smile

I have checked your demo and now it works well. In a big program where I have applied it, it works well too Smile.

You have done more changes than just a fix Wink. You have removed dependencies to packages Web and Web/SSL.

This afternoon I will upload it to Bazaar. In some hours I will propose a possible application of your useful functions.

Great job !


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25410 is a reply to message #23087] Mon, 22 February 2010 11:55 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

I have compiled OpenSSL in MinGW, although only obtaining .dll Sad. It is very easy.

If you want I can include it in T++.


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25412 is a reply to message #25410] Mon, 22 February 2010 12:24 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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Yes, it would be great to add article "Building OpenSSL with MINGW under Windows" and add its reference into tutorial article.
Great work, Koldo, and thanks for checking out my AESStreams!
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25415 is a reply to message #25412] Mon, 22 February 2010 12:46 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

Your package is very useful.

If somebody requires to encrypt seriously a String or raw data from small size to Gb, this is a simple way to do it Smile.

This is not an encryption algorithms catalog. This is just one of the best options with an easy interface.


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25420 is a reply to message #25415] Mon, 22 February 2010 15:19 Go to previous messageGo to next message
tojocky is currently offline  tojocky
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Koldo,

Can you ad in BAZAAR?

Than you Koldo, and Mindtraveller!

Regards, ion Lupascu (tojocky).

koldo wrote on Mon, 22 February 2010 13:46

Hello Mindtraveller

Your package is very useful.

If somebody requires to encrypt seriously a String or raw data from small size to Gb, this is a simple way to do it Smile.

This is not an encryption algorithms catalog. This is just one of the best options with an easy interface.

Re: Encrypted storage with streaming (OpenSSL, AES) [message #25422 is a reply to message #25420] Mon, 22 February 2010 16:46 Go to previous messageGo to next message
koldo is currently offline  koldo
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tojocky wrote on Mon, 22 February 2010 15:19

Koldo,

Can you ad in BAZAAR?

Than you Koldo, and Mindtraveller!

Regards, ion Lupascu (tojocky).

koldo wrote on Mon, 22 February 2010 13:46

Hello Mindtraveller

Your package is very useful.

If somebody requires to encrypt seriously a String or raw data from small size to Gb, this is a simple way to do it Smile.

This is not an encryption algorithms catalog. This is just one of the best options with an easy interface.




Quote:

This afternoon I will upload it to Bazaar.

Yes. In a few UTC hours Smile


Best regards
Iñaki
Building with MSC9 [message #25617 is a reply to message #25422] Wed, 03 March 2010 23:17 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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hi people, great work...

compile with MSC9 worked great, both static and dynamic.
2 quick corrections / hints, though

1) using MSC9 stuff the command is
C:\Temp\openssl-0.9.8m> %comspec% /k ""c:\Program Files\Microsoft Visual Studio 9.0\VC\bin\vcvars32.bat"" x86


2) the out32/ folder offset for the *.lib stuff should be removed in package organizer of AESStreamTest, since the build method setup for LIB stuff already points to "C:\Temp\openssl-0.9.8m\out32"
Re: Building with MSC9 [message #25648 is a reply to message #25617] Sat, 06 March 2010 01:49 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Kohait00

Quote:

C:\Temp\openssl-0.9.8m> %comspec% /k ""c:\Program Files\Microsoft Visual Studio 9.0\VC\bin\vcvars32.bat"" x86

Included

Quote:

the out32/ folder offset for the *.lib stuff should be removed in package organizer of AESStreamTest, since the build method setup for LIB stuff already points to "C:\Temp\openssl-0.9.8m\out32"


Sorry, I do not understand.


Best regards
Iñaki
Re: Building with MSC9 [message #25668 is a reply to message #25648] Sun, 07 March 2010 11:24 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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hi koldo,

i meant the following:

according to the instructions provided, the LIB directories are to be set to "C:\Temp\openssl-0.9.8m\out32", but in package organizer, the AESStream package includes "out32/libeay32.lib" or "out32dll/libeay32.lib" depending on flags.. this wont work, the libs wont be found.

the LIB directories entry should be set to "C:\Temp\openssl-0.9.8m", thats all.. sorry for misleading post.
Re: Building with MSC9 [message #25674 is a reply to message #25668] Sun, 07 March 2010 13:47 Go to previous messageGo to next message
koldo is currently offline  koldo
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kohait00 wrote on Sun, 07 March 2010 11:24

hi koldo,

i meant the following:

according to the instructions provided, the LIB directories are to be set to "C:\Temp\openssl-0.9.8m\out32", but in package organizer, the AESStream package includes "out32/libeay32.lib" or "out32dll/libeay32.lib" depending on flags.. this wont work, the libs wont be found.

the LIB directories entry should be set to "C:\Temp\openssl-0.9.8m", thats all.. sorry for misleading post.

Hello Kohait00

Now in AESStream doc it appears in the setup the next description:

Quote:

...

2.5. The result is in next folders:
inc32: Include files
out32: *.lib files for static linking
out32dll: *.lib & *.dll files for dynamic linking

...

2.6. Add in "Setup/Build methods/Lib directories" menu, the directory where out32 and out32dll have been copied.


Is it ok ?

And sorry. Your post was not misleading. Just hard to understand for me Razz


Best regards
Iñaki
Re: Building with MSC9 [message #25677 is a reply to message #25674] Sun, 07 March 2010 16:08 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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thnak you, no problem.
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25758 is a reply to message #23087] Wed, 10 March 2010 17:09 Go to previous messageGo to next message
koldo is currently offline  koldo
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Hello Mindtraveller

Could you add in AESStream the possibility of accepting keys with length different that 32, 16, ..., perhaps using the SHA-256 algorithm as you suggested before ?


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25762 is a reply to message #25758] Wed, 10 March 2010 20:54 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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hi koldo,

as far as i got the point of mindtraveler, AES and the other symetric algorithms are not to be thought of beeing based on a "password", a user defined and therefore week combination of signs (which would be scanned first in a brute force attack), but on a statistically well distributed *binary* key (128 bit should be made wise Smile. it is hard for a human beeing to generate one. so the computer will take over and provide some random ones(AES key generator). this key should be thought of as a "password", what it of corse isn't. everything else would diminish the stability of the key.
maybe to get over it, think of it as kind a GUID which you generate once for your application (which in real world communication does not apply Smile. dont think of AES as sort of alphanumerical password dependant encryption algorithm, it's indeed, just as mindtraveler mentioned: math. i had the luck to enjoy some lectures cryptology, and it confuses sometimes. but the first thing we learned there was to forget the idea of passwords / human readable strings as security base.
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25763 is a reply to message #25762] Wed, 10 March 2010 21:33 Go to previous messageGo to next message
koldo is currently offline  koldo
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kohait00 wrote on Wed, 10 March 2010 20:54

hi koldo,

as far as i got the point of mindtraveler, AES and the other symetric algorithms are not to be thought of beeing based on a "password", a user defined and therefore week combination of signs (which would be scanned first in a brute force attack), but on a statistically well distributed *binary* key (128 bit should be made wise Smile. it is hard for a human beeing to generate one. so the computer will take over and provide some random ones(AES key generator). this key should be thought of as a "password", what it of corse isn't. everything else would diminish the stability of the key.
maybe to get over it, think of it as kind a GUID which you generate once for your application (which in real world communication does not apply Smile. dont think of AES as sort of alphanumerical password dependant encryption algorithm, it's indeed, just as mindtraveler mentioned: math. i had the luck to enjoy some lectures cryptology, and it confuses sometimes. but the first thing we learned there was to forget the idea of passwords / human readable strings as security base.

Yes yes, all of you are right Smile

However think about for example a file encrypting software to be used by different people. How would you do it ?

Option 1: The software gives the user a 32 bytes random key
Option 2: The user enters a key


Option 1 seems much stronger. However file and hard disk encrypting software seems to choose option 2.


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25767 is a reply to message #25763] Wed, 10 March 2010 22:36 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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http://www.winzip.com/aes_info.htm
should explain that its not trivial Smile
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25770 is a reply to message #25767] Thu, 11 March 2010 09:12 Go to previous messageGo to next message
koldo is currently offline  koldo
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kohait00 wrote on Wed, 10 March 2010 22:36

http://www.winzip.com/aes_info.htm
should explain that its not trivial Smile

Hello Kohait00

Thank you for the reference. I will use it.

Coming to the issue, look at this:

- If it is open source, I cannot put the key in the code

- If the program creates a key for the user, and he/she is not let to change it, a 32 bytes password seems too hard to use

- If we use a user defined key, we could include in AESStream:

---1. A SHA 256 possibility to convert user password in a 32 bytes key
---2. The means to avoid a brute force attack.
For example, if AES 256 with a weak user key can resist within and acceptable probability, for example, 1000000 random keys, AESStream could let the main program to enter, for example, 1000 keys per day and after that, AESStream would refuse any additional key.


Best regards
Iñaki
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25772 is a reply to message #25770] Thu, 11 March 2010 10:29 Go to previous messageGo to next message
kohait00 is currently offline  kohait00
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i dont know if i remember it correctly, but there are several technices combined to achieve encryption of data trggered by a user password.

1) the en/de cryption is done using a *fast* (symetrical) algorithm, like AES (they are blockorientated and relatively similar, only differ in their block functions (F functions, or Feistel Function)

2) the key used there, is the key we were speaking about, and is encrypted and stored with the data. as encryption can be used slow but really strong asymetrical (public / private key) algorithms like RSA.

3) the password thing comes into play with things like diffie hellman secure exchage of information with having it travel over the net.

but its quite a while now, and i may mix it up with things like vpn tunneling and handshaking and so on..

but in any way: encrypting decrypting to fit current standards is far from beeing trivial and involves a lot of steps, password is only a small part of it, maybe we should stick to common technologie here (means in openssl)
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25773 is a reply to message #25772] Thu, 11 March 2010 10:53 Go to previous messageGo to next message
Mindtraveller is currently offline  Mindtraveller
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The truth is that you MUST
1) Use strong key with AES, not password
2) Not to hardcode the key in the code in ANY way

So what is the solution? You take user password. And then you DERIVE strong key from it. Then you "forget" user password, you just don't need it at all. You do encryption with that relatively strong key (i.e. SHA from user password - see my recent comment).

Next time user enters password, you derive the key with the same function (i.e. SHA) and try to decompress AESStream. If decomression fails, then original password and the one entered is not the same (incorrect password).

It is really not that hard.
Re: Encrypted storage with streaming (OpenSSL, AES) [message #25774 is a reply to message #25773] Thu, 11 March 2010 11:01 Go to previous messageGo to previous message
koldo is currently offline  koldo
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Mindtraveller wrote on Thu, 11 March 2010 10:53

The truth is that you MUST
1) Use strong key with AES, not password
2) Not to hardcode the key in the code in ANY way

So what is the solution? You take user password. And then you DERIVE strong key from it. Then you "forget" user password, you just don't need it at all. You do encryption with that relatively strong key (i.e. SHA from user password - see my recent comment).

Next time user enters password, you derive the key with the same function (i.e. SHA) and try to decompress AESStream. If decomression fails, then original password and the one entered is not the same (incorrect password).

It is really not that hard.

Could you implement this in AESStream ?


Best regards
Iñaki
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