[Botan-devel] DES and Tripple DES example needed

[Brian Mitchell]

Thanks Jack

Brian

On Thursday 01 March 2007 14:29, Jack Lloyd wrote:
> The particular problem you're seeing is two-fold: you must construct a
> LibraryInitalizer object or a number of operations (such as memory
> allocation, which the DES object will need) fail. When those
> operations fail, they throw an exception. However you don't have
> toplevel try {} catch(...) block in your main(), so instead the C++
> runtime aborts the program (through std::terminate()). Some runtimes
> print a helpful message inside terminate() telling you what happened,
> most just call abort().  With a try/catch and a printf you should
> start seeing a message about how the library was not initialized
> before use.
>
> Following is an example that may help (which I have not compiled, so
> there may be minor problems, but it should at least help point you in
> the right direction in the documentation). To use 3DES instead of DES,
> all that is needed is to replace the strings "DES/CBC" with
> "TripleDES/CBC" and increase the sizes of all the keys to 192 bits/24
> bytes. Unless you need block level processing for some reason, it's a
> lot more convenient and simple to use Pipe and let it handle the
> buffering and such for you.
>
> Hope this helps,
>   Jack
>
> #include <botan/botan.h>
> #include <botan/des.h>
> #include <stdio.h>
>
> using namespace Botan;
>
> SecureVector<byte> encrypt(const char*, const SymmetricKey&);
> std::string decrypt(const SecureVector<byte>&, const SymmetricKey&);
>
> int main()
>    {
>    LibraryInitializer init; // needed or nothing will work
>
>    const char* msg = "Hello world\n"; // can be any length, we don't care
>    SymmetricKey key("ABCDEF0123456789"); // 64 bits
>
>    // SymmetricKey key(8); // a random 64-bit key
>
>    SecureVector<byte> ciphertext = encrypt(msg, key);
>
>    std::string plaintext = decrypt(ciphertext, key);
>
>    printf("%s\n", plaintext.c_str());
>    }
>
> SecureVector<byte> encrypt(const char* msg, const SymmetricKey& key)
>    {
>    Pipe pipe(get_cipher("DES/CBC", key, ENCRYPTION));
>    pipe.start_msg();
>    pipe.write(msg, strlen(msg));
>    pipe.end_msg();
>
>    return pipe.read_all();
>    }
>
> std::string decrypt(const SecureVector<byte>& msg,
>                     const SymmetricKey& key)
>    {
>    Pipe pipe(get_cipher("DES/CBC", key, DECRYPTION));
>    pipe.start_msg();
>    pipe.write(msg);
>    pipe.end_msg();
>
>    return pipe.read_all_as_string();
>    }
>
> On Thu, Mar 01, 2007 at 01:58:23PM +0000, Brian Mitchell wrote:
> > Hi,
> >
> > ????????I'm trying to use Botan to do a very simple DES calculation. In
> > reality it
> > will need to be Tripple DES, but I can't even get a straight forward DES
> > calculation working yet. Has anybody got a very simple, make a key, make
> > a buffer and encrypt it program?
> >
> > I have appended my simple program, but that always aborts when I
> > construct DES.
> > If anyone has information on how to use Tripple DES that would be very
> > nice.
> >
> > Thanks
> >
> > Brian.
> >
> >
> > #include <botan/des.h>
> >
> > using namespace Botan;
> >
> > int main()
> > {
> > ????????byte ?inblock[80] ? ? ?= {"11111111"};
> > ????????byte ?outblock[80];
> > ????????byte ?origblock[80];
> >
> > ????????byte ?key[80] = {"11111111"};
> >
> > ????????DES des;
> > ????????u32bit kl = 8;??
> > ????????des.set_key(key,kl);
> > ????????des.encrypt(inblock, outblock);
> > ????????des.decrypt(outblock, origblock);
> >
> > ????????return 1;
> > }
> >
> > _______________________________________________
> > botan-devel mailing list
> > botan-devel at randombit.net
> > http://www.randombit.net/mailman/listinfo/botan-devel
>
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