[Botan-devel] AES cipher refuses to work

Marcus Proest marcus at proest.net
Tue Jan 11 10:49:16 EST 2005


Argh, stupid me.

It works, thanks!

Marc

Jack Lloyd wrote:
>18 bytes == 144 bits. For a 128-bit key, you want to use 16 bytes.
>
>-Jack
>
>On Tue, Jan 11, 2005 at 01:15:50PM +0100, Marcus Proest wrote:
>  
>>Hi there,
>>
>>please consider the following code:
>>
>>#include <botan/botan.h>
>>#include <fstream>
>>#include <iostream>
>>#define KEYL 18
>>
>>int main() {
>>  try {
>>      Botan::LibraryInitializer init("thread_safe use_engines");
>>
>>      Botan::byte i[KEYL];
>>      for(int x=0;x<KEYL;x++) i[x]=0;   //testing with a "0" key
>>
>>      Botan::SymmetricKey key(i,KEYL);   //instantiate key
>>      Botan::Pipe pipe(Botan::get_cipher("AES/ECB", key, 
>>Botan::DECRYPTION)); //create pipe !exeption here!
>>
>>      std::ofstream outfile("/tmp/plaintext");
>>      std::ifstream infile("/tmp/ciphered");
>>
>>      pipe.start_msg();
>>      infile >> pipe;
>>      pipe.end_msg();
>>      outfile << pipe;
>>
>>  } catch (std::exception &e) {
>>      std::cerr << "exc caught: " << e.what() << std::endl;
>>  }
>>  return 0;
>>}
>>
>>The output of the above code ist:
>>
>>  exc caught: Botan: AES cannot accept a key of length 18
>>
>>A key length of 18 should be 18 byte = 256 bit, or am i missing something?
>>Nevertheless, even setting KEYL to 17 (=128 bit), 128, 192 or 256 is not 
>>resulting in success.
>>
>>The Algorithms seem to be installed properly, since
>>
>>  /usr/src/Botan-1.4.4> ./check --bench-block
>>
>>gives me
>>  AES-128:                    29.90 Mbytes/sec
>>  AES-192:                    26.25 Mbytes/sec
>>  AES-256:                    23.38 Mbytes/sec
>>  Blowfish:                   20.10 Mbytes/sec
>>  ...
>>
>>Can somebody tell me what i am doing wrong?
>>
>>Regards,
>>
>>Marc
>>
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>>    




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