So far my code looks like this...

VMAC<AES, 128> myMac;
myMac.UncheckedSetKey(userKey, MY_KEY_LENGTH, g_nullNameValuePairs);
myMac.Update(myData, myDataSize);
myMac.Final(myHashValue);

I believe I need to do much more to initialize the VMAC class because I am 
getting the following failure messages when I run the exe:

CryptoPP::Exception caught: VMAC(AES)-128: this object requires an IV

I have tried to replace the g_nullNameValuePairs with a flushed out object, 
but it is unclear to me how I set up (initialize) the necessary 
NameValuePairs object. I can't find any doc on this. Does anyone have a 
good example of this that they are willing to share?

Also, what exactly is an IV?

Bill


On Tuesday, September 18, 2012 4:32:56 PM UTC-4, Bill Santo wrote:
>
> Please forgive my basic question, and please redirect me to a different 
> resource if appropriate.
>
> I want to use the cryptopp library to generate a 128 bit hash value using 
> the vhash algorithm. I've been studying the vmac and iterhash class 
> interfaces and code. I think I must invoke Update(...) specifying the input 
> data block and its size. The final hash value can then be retrieved using 
> TruncatedFinal(...). Or, if the data is in one contiguous block, I can call 
> CalculatedDigest() instead. Is this correct?
>
> Is there other setup or initialization of the vhash or other cryptopp code 
> that is required prior to these calls?
>
> I've seen the SHA example in the User's Guide ( 
> http://www.cryptopp.com/wiki/Hash ) which implies that these are the only 
> method calls needed.
>
> Thanks to anyone who can point me in the right direction. I want to be 
> sure I am generating correct hash values.
>
> Bill
>
>

-- 
You received this message because you are subscribed to the "Crypto++ Users" 
Google Group.
To unsubscribe, send an email to [email protected].
More information about Crypto++ and this group is available at 
http://www.cryptopp.com.

Reply via email to