Reference Code

F.4 Reference Code

The following code implements the calculations of H(A1), H(A2), request-digest, and response-digest, from RFC 2617. It uses the MD5 implementation from RFC 1321.

F.4.1 File " digcalc .h"

  #define HASHLEN 16  

  typedef char HASH[HASHLEN];  

  #define HASHHEXLEN 32  

  typedef char HASHHEX[HASHHEXLEN+1];  

  #define IN  

  #define OUT  

  /* calculate H(A1) as per HTTP Digest spec */  

  void DigestCalcHA1(  

  IN char * pszAlg,  

  IN char * pszUserName,  

  IN char * pszRealm,  

  IN char * pszPassword,  

  IN char * pszNonce,  

   IN char * pszCNonce, 

 OUT HASHHEX SessionKey 

 ); 

 /* calculate request-digest/response-digest as per HTTP Digest spec */ 

 void DigestCalcResponse( 

 IN HASHHEX HA1, /* H(A1) */ 

 IN char * pszNonce, /* nonce from server */ 

 IN char * pszNonceCount, /* 8 hex digits */ 

 IN char * pszCNonce, /* client nonce */ 

 IN char * pszQop, /* qop-value: "", "auth", "auth-int" */ 

 IN char * pszMethod, /* method from the request */ 

 IN char * pszDigestUri, /* requested URL */ 

 IN HASHHEX HEntity, /* H(entity body) if qop="auth-int" */ 

 OUT HASHHEX Response /* request-digest or response-digest */ 

 ); 

F.4.2 File "digcalc.c"

 #include <global.h> 

 #include <md5.h> 

 #include <string.h> 

 #include "digcalc.h" 

 void CvtHex( 

 IN HASH Bin, 

 OUT HASHHEX Hex 

 ) 

 { 

 unsigned short i; 

 unsigned char j; 

 for (i = 0; i < HASHLEN; i++) { 

 j = (Bin[i] >> 4) & 0xf; 

 if (j <= 9) 

 Hex[i*2] = (j + '0'); 

 else 

 Hex[i*2] = (j + 'a' - 10); 

 j = Bin[i] & 0xf; 

 if (j <= 9) 

 Hex[i*2+1] = (j + '0'); 

 else 

 Hex[i*2+1] = (j + 'a' - 10); 

 }; 

 Hex[HASHHEXLEN] = ' 
 Hex[HASHHEXLEN] = '\0'; 
 '; 

 }; 

 /* calculate H(A1) as per spec */ 

 void DigestCalcHA1( 

 IN char * pszAlg, 

 IN char * pszUserName, 

 IN char * pszRealm, 

 IN char * pszPassword, 

 IN char * pszNonce, 

 IN char * pszCNonce, 

 OUT HASHHEX SessionKey 

 ) 

 { 

 MD5_CTX Md5Ctx; 

 HASH HA1; 

 MD5Init(&Md5Ctx); 

 MD5Update(&Md5Ctx, pszUserName, strlen(pszUserName)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszRealm, strlen(pszRealm)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszPassword, strlen(pszPassword)); 

 MD5Final(HA1, &Md5Ctx); 

 if (stricmp(pszAlg, "md5-sess") == 0) { 

 MD5Init(&Md5Ctx); 

 MD5Update(&Md5Ctx, HA1, HASHLEN); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce)); 

 MD5Final(HA1, &Md5Ctx); 

 }; 

 CvtHex(HA1, SessionKey); 

 }; 

 /* calculate request-digest/response-digest as per HTTP Digest spec */ 

 void DigestCalcResponse( 

 IN HASHHEX HA1, /* H(A1) */ 

 IN char * pszNonce, /* nonce from server */ 

 IN char * pszNonceCount, /* 8 hex digits */ 

 IN char * pszCNonce, /* client nonce */ 

 IN char * pszQop, /* qop-value: "", "auth", "auth-int" */ 

 IN char * pszMethod, /* method from the request */ 

 IN char * pszDigestUri, /* requested URL */ 

 IN HASHHEX HEntity, /* H(entity body) if qop="auth-int" */ 

 OUT HASHHEX Response /* request-digest or response-digest */ 

 ) 

 { 

 MD5_CTX Md5Ctx; 

 HASH HA2; 

 HASH RespHash; 

 HASHHEX HA2Hex; 

 // calculate H(A2) 

 MD5Init(&Md5Ctx); 

 MD5Update(&Md5Ctx, pszMethod, strlen(pszMethod)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszDigestUri, strlen(pszDigestUri)); 

 if (stricmp(pszQop, "auth-int") == 0) { 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, HEntity, HASHHEXLEN); 

 }; 

 MD5Final(HA2, &Md5Ctx); 

 CvtHex(HA2, HA2Hex); 

 // calculate response 

 MD5Init(&Md5Ctx); 

 MD5Update(&Md5Ctx, HA1, HASHHEXLEN); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszNonce, strlen(pszNonce)); 

 MD5Update(&Md5Ctx, ":", 1); 

 if (*pszQop) { 

 MD5Update(&Md5Ctx, pszNonceCount, strlen(pszNonceCount)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszCNonce, strlen(pszCNonce)); 

 MD5Update(&Md5Ctx, ":", 1); 

 MD5Update(&Md5Ctx, pszQop, strlen(pszQop)); 

 MD5Update(&Md5Ctx, ":", 1); 

 }; 

 MD5Update(&Md5Ctx, HA2Hex, HASHHEXLEN); 

 MD5Final(RespHash, &Md5Ctx); 

 CvtHex(RespHash, Response); 

 }; 

F.4.3 File "digtest.c"

 #include <stdio.h> 

 #include "digcalc.h" 

 void main(int argc, char ** argv) { 

 char * pszNonce = "dcd98b7102dd2f0e8b11d0f600bfb0c093"; 

 char * pszCNonce = "0a4f113b"; 

 char * pszUser = "Mufasa"; 

 char * pszRealm = "[e-mail]"; 

 char * pszPass = "Circle Of Life"; 

 char * pszAlg = "md5"; 

 char szNonceCount[9] = "00000001"; 

 char * pszMethod = "GET"; 

 char * pszQop = "auth"; 

 char * pszURI = "/dir/index.html"; 

 HASHHEX HA1; 

 HASHHEX HA2 = ""; 

 HASHHEX Response; 

 DigestCalcHA1(pszAlg, pszUser, pszRealm, pszPass, 

 pszNonce, pszCNonce, HA1); 

 DigestCalcResponse(HA1, pszNonce, szNonceCount, pszCNonce, pszQop, 

 pszMethod, pszURI, HA2, Response); 

 printf("Response = %s\n", Response); 

 };