C++ pretty output of SHA 256

[roelj]

I'm facing a problem and I don't know how I can solve it / I don't know where to search.

I'm using botan to generate a SHA-256 check sum and I want it to output it as (I think) modhex.

Though, the output is like:

L�y�����B��Fs!�)�v&�VG

The output should be something like:

b8ed91da716fc576e3d005d91a9bdab842288439

I tried using:

cout << setbase(16) << sha256str << endl;

But it doesn't make a difference at all.

What can I do or what should I know?

---------- Post added at 02:04 PM ---------- Previous post was at 02:56 AM ----------

I should've read more of the Botan documentation. Something like:

Botan::Pipe pipe(new Botan::Hex_Encoder);

Can convert the output to hexadecimal output.

Now, I wonder, what's the output format of the sha1sum application?

[RupertPupkin]

Originally Posted by roelj

what's the output format of the sha1sum application?

sha1sum and sha256sum both use hexadecimal output:

$ echo -n hello | sha1sum -
aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d
$ echo -n hello | sha256sum -
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824

[roelj]

Thanks for your reply.

I've got the sha256 check sums looking equal to the sha256 software now with the following:

std::string sha256::process(std::string message) {

  /* Botan pipe to process messages.
   * First make a SHA-256 hash and then apply
   * the hexadecimal format for output on it.
   */
  Botan::Pipe pipe(
    new Botan::Chain(
      new Botan::Hash_Filter(new Botan::SHA_256),
      new Botan::Hex_Encoder)
    );

  pipe.process_msg(message);
  buffer = pipe.read_all_as_string(0);

  boost::to_lower(buffer);
  return buffer;
}

In case anyone is using Botan and Boost as well and wants to get it to work.

[RupertPupkin]

Cool, I'd never heard of the Botan library before. For doing that sort of thing programatically I'd used Python:

>>> import hashlib
>>> print hashlib.sha256("hello").hexdigest()
2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824