Thanks for the examples. I'm gonna test them now!
Carter Browne wrote:
>
> You need to look at your data to see how the bytes are swapped:
> 3 common patterns:
>
> 1) Even odd bytes are swapped
> 2) The data was treated as 32 bit, one system is little ended and the
> other big ended.
> 3) The entire buffer is reversed.
>
> Assume pcBuffer is the char * pointer to your data, uiLen is the
> unsigned length of the data.
>
> For 1)
>
> char acTemp = new char[ uiLen ];
>
> _swab(pcBuffer,acTemp,uiLen);
> memcpy(pcBuffer,acTemp,uiLen);
> delete acTemp;
>
> Note: uiLen is assumed to be even
>
> For 2)
>
> char cTemp;
> int i,j;
>
> for (i=0;i<uiLen;i+=4)
> {
> for (j=0;j<2;j++)
> {
> cTemp = pcBuffer[ i+j];
> pcBuffer[ i+j ] = pcBuffer[ i+3-j ];
> pcBuffer[ i+3-j] = cTemp;
> }
>
> Note: This code assumes that uiLen is a multiple of 4;
>
>
> For 3)
>
> char cTemp;
>
> for (i=0;i<uiLen/2;i++)
> {
> cTemp = pcBuffer[ i];
> pcBuffer[ i ] = pcBuffer[ i+uiLen-i-1 ];
> pcBuffer[ i+uiLen-i-1] = cTemp;
> }
>
> Carter
>
>
> Carter Browne
> CBCS
> cbro...@cbcs-usa.com
> 781-721-2890
>
>
>
> Goblin_Queen wrote:
>> Yes, I know that, but I don't know how to do that in code. I've found the
>> following post:
>> http://stackoverflow.com/questions/105252/how-do-i-convert-between-big-endian-and-little-endian-values-in-c
>> http://stackoverflow.com/questions/105252/how-do-i-convert-between-big-endian-and-little-endian-values-in-c
>>
>> where I've tried the method with the template<>, which definitely didn't
>> give me a correct result.
>> On that forum they're saying that char's don't have to be converted, but
>> is
>> that true?
>>
>> Would it be possible for you to provide me with a code sample on how to
>> convert a char* to little endian? I know it's probably a stupid question
>> and
>> I'm taking up your time, but I have to learn it somehow...
>> Thanks in advance!
>>
>>
>>
>> Goblin_Queen wrote:
>>
>>> Thanks for your reply, I had thought of that too because my search lead
>>> me
>>> to such an answer. How can I convert a char* from big endian to little
>>> endian? I googled for conversion examples but I only found conversions
>>> for
>>> int. I know this is probably a stupid question, but I'm still learning
>>> C++.
>>>
>>>
>>> Dr. Stephen Henson wrote:
>>>
>>>> On Wed, Mar 18, 2009, Goblin_Queen wrote:
>>>>
>>>>
>>>>> Hello,
>>>>>
>>>>> I'm writing a program that has to sign a SHA1-hash value. I'm using
>>>>> OpenSSL
>>>>> to do this. My program has to do the same thing as another program
>>>>> which
>>>>> makes use of Microsoft Crypto API. In that program the method
>>>>> "CryptSignHash" was used in order to sign the hash value.
>>>>>
>>>>> When I try to sign a dummy hash value with RSA_sign, the result is
>>>>> different
>>>>> from the result I get from CryptSignHash. I've been searching for a
>>>>> while to
>>>>> find the reason for this, but haven't found the solution yet.
>>>>>
>>>>> I've also tried to sign the hash with other signature methods in
>>>>> OpenSSL:
>>>>> RSA_private_encrypt and EVP_SignFinal. Those gave me an error when I
>>>>> tried
>>>>> them, but I don't really know the difference between those 3 methods,
>>>>> the
>>>>> documentation isn't very clear, and I'm very new to cryptography
>>>>> functions
>>>>> and OpenSSL.
>>>>>
>>>>> Can anyone help me with this and tell me what I should use to get the
>>>>> same
>>>>> result as CryptSignHash returns?
>>>>>
>>>>> If you need to see my code in order to help me, just ask, then I'll
>>>>> post
>>>>> it.
>>>>>
>>>> The output of CryptoAPI is in little endian format, OpenSSL and many
>>>> others
>>>> use big endian. Try reversing the bytes.
>>>>
>>>> Steve.
>>>> --
>>>> Dr Stephen N. Henson. Email, S/MIME and PGP keys: see homepage
>>>> OpenSSL project core developer and freelance consultant.
>>>> Homepage: http://www.drh-consultancy.demon.co.uk
>>>> ______________________________________________________________________
>>>> OpenSSL Project http://www.openssl.org
>>>> User Support Mailing List openssl-users@openssl.org
>>>> Automated List Manager majord...@openssl.org
>>>>
>>>>
>>>>
>>>
>>>
>>
>>
> ______________________________________________________________________
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>
>
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