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C++ Class Implementation of HMAC-SHA

, 2 May 2010 CPOL
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C++ class of HMAC-SHA1


This is my first article on CodeProject. Sorry for my poor English.

The reason I think it might be helpful that I share this HMAC-SHA1 class is because I found no related source I could refer to. This is a simple C++ class of HMAC-SHA1 with only single byte character support. You could add double bytes character support if needed. You will find this class contains only a function HMAC_SHA1 that accept test input and hash key, then generates a digest.


Thanks to Dominik Reichl, the SHA1 class I wrapped is from his amazing class. I simply implemented the HMAC algorithm on it. For MD5, you could refer to RFC. There is a detailed programming flow of it.

Using the Code

The usage of this class is extremely simple. Declare CHMAC_SHA1, call its HMAC_SHA1 function. That's it!

You may use HMAC-SHA1 in RFC 2202 test case to verify your implementation.

Following is test case 1 in RFC 2202.

#include "HMAC_SHA1.h"
BYTE Key[20] ;
BYTE digest[20] ; 

unsigned char *test = "Hi There" ; 
memset(Key, 0x0b, 20) ;
HMAC_SHA1.HMAC_SHA1(test, strlen(test), Key, sizeof(Key), digest) ;
// Check with digest equal to 0xb617318655057264e28bc0b6fb378c8ef146be00
// or not


  • 2007/12/17: Updated sample code with RFC 2202 test case 1


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Chien-Chung, Chung
Software Developer (Senior)
Taiwan Taiwan
Life is nothing but choices.

Comments and Discussions

GeneralMy vote of 5 Pinmembernicklin026-Mar-13 4:57 
QuestionCode Segfaults with messages longer than buffersize minus digestsize PinmemberMember 932791917-Sep-12 7:16 
QuestionIs the digest same as the one computed by C# code ? PinmemberBeckDai12-Apr-12 18:55 
AnswerRe: Is the digest same as the one computed by C# code ? PinmemberChien-Chung, Chung7-May-12 23:49 
Questionthe result is not right Pinmemberhaolifengwang1-Jan-12 19:49 
AnswerRe: the result is not right PinmemberChien-Chung, Chung7-May-12 23:47 
Generalhelp me Pinmemberkalyan41927-Aug-09 19:41 
QuestionError message PinmemberGodwin Ansa5-Aug-08 4:05 
AnswerRe: Error message PinmemberChien-Chung, Chung2-May-10 17:38 
Have you add the CSHA files to your project ???
What kind of platform you are using for this proejct ???
You will get the errors because the compiler checks syntax for the pointer to a string as a const pointer.
And parameter 1 for CHMAC_SHA1 is a pointer to unsigned char.
Try to cast the "unsigned char * test" to "const char * test".
Generalmemset used wrongly PinmemberDante Shamest21-Jul-08 22:06 
GeneralRe: memset used wrongly Pinmemberhetcorp1-Apr-09 5:41 
GeneralRe: memset used wrongly PinmemberJim Chung2-May-10 17:10 
Questionreceiver processing for HMAC-SHA? PinmemberAdam Harding3-Jun-08 13:49 
GeneralBugfix for long key's [modified] Pinmemberbruno19996-Mar-08 4:31 
GeneralThanks Pinmemberbruno19995-Mar-08 10:37 
GeneralRe: Thanks PinmemberGodwin Ansa27-Aug-08 4:01 

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