예제 C 프로그램: CertOIDToAlgId 및 CertCompareIntegerBlob 사용

다음 예제에서는 CertOIDToAlgId 및 CertCompareIntegerBlob 함수를 사용하는 방법을 보여 줍니다.

먼저 사용 가능한 모든 OID는 CryptEnumOIDInfo를 사용하여 열거됩니다. 이 함수와 함께 사용되는 코드는 콜백 함수의 사용도 보여 줍니다. 콜백 함수는 각 OID 그룹과 설정된 수의 OID에 대한 정보를 표시한 후 일시 중지하는 중단 논리를 보여 줍니다.

둘째, CertOIDToAlgId를 사용하여 3개의 OID(개체 식별자) 문자열이 DWORD 알고리즘 식별자 정수로 변환됩니다. 또한 이 코드는 모든 OID 문자열에 관련 알고리즘 식별자가 없음을 보여 줍니다.

마지막으로, 이 예제에서는 정수 BLOB을 비교하는 방법을 보여 줍니다. 이 예제에서는 양수에서 선행 0x00 잘림과 음수에서 선행 0xFF 잘림을 보여 줍니다.

또한 정수는 오른쪽에 가장 중요한 숫자가 있는 little-endian 형식으로 저장된 것처럼 비교됩니다.

#pragma comment(lib, "crypt32.lib")

#include <windows.h>
#include <stdio.h>
#include <Wincrypt.h>

//-------------------------------------------------------------------
// Copyright (C) Microsoft.  All rights reserved.
// Declare a wait function to be defined following main.

void my_wait(char *s);

//-------------------------------------------------------------------
// Callback function to print information
// saved in each CRYPT_OID_INFO structure.
// This function counts the number of lines printed
// and does a wait for each new ground and after any four
// report groups are printed.

static BOOL WINAPI EnumInfoCallback(
     PCCRYPT_OID_INFO pInfo,
     void *pvArg
    )
{
static int old_oid = 0;
static int break_counter = 0;

if( old_oid < pInfo->dwGroupId)
{
     if(old_oid > 0)
     {
          my_wait("\n Begin new group. \n Hit enter to continue.");
          break_counter=0;
     }
     old_oid = pInfo->dwGroupId;
     printf("\nNew Group ID %d \n",old_oid);
}
printf("  OID: %s\n  Name: %S\n",
       pInfo->pszOID, pInfo->pwszName);

//-------------------------------------------------------------------
// If there is an AlgId, print it.

if( pInfo->Algid > 0)
{
     printf("  Algorithm ID hexadecimal %x \n\n",pInfo->Algid);
}
else
{
     printf("\n");
}

if(++break_counter > 4)
{ 
     break_counter = 0;
     my_wait("\n   Hit enter to continue.");
}
return TRUE;
}

void main()
{
//-------------------------------------------------------------------
// Note: Integer BLOBs are treated as if they
// are stored in little-endian form with the 
// most significant digits on the right. Truncation is 
// therefore from the right.
// Integer BLOBs are also assumed to be signed numbers
// in two's compliment form.
// For negative numbers, 0xFFs on the right are 
// truncated.
// For positive numbers, 0x00s on the right are 
// truncated.

//-------------------------------------------------------------------
// Declare and initialize local variables.

DWORD Alg_Id;
CRYPT_INTEGER_BLOB  Int1, Int2;
BYTE BLOB1data[4] = {0x88, 0xFF, 0xFF, 0xFF};
BYTE BLOB2data[2] = {0x88, 0xFF};
BYTE BLOB3data[4] = {0x01, 0x00, 0x00, 0x00};
BYTE BLOB4data[2] = {0x01, 0x00};
BYTE BLOB5data[4] = {0x01, 0x00, 0x01, 0x00};

//-------------------------------------------------------------------
// Enumerate the algorithm OIDs available.
// Note that this one call to the function with
// dwGroupId set to 0 lists all OIDs in all groups. 

if(!(CryptEnumOIDInfo(
    0,                  // use 0 to enumerate the OIDs in all groups
    0,                  // dwFlags
    NULL,               // no additional parameters are to be 
                        // passed to the callback function.
    EnumInfoCallback    // name of the callback function to be 
                        // called for each OID enumerated.
    )))
{
    printf("Enumeration of algorithm OIDs did not complete.\n");
}

//-------------------------------------------------------------------
// Use CertOIDToAlgId() to 
// convert the szOID_RSA_RC4 Object Identifier string to an 
// algorithm identifier.

if( Alg_Id = CertOIDToAlgId(szOID_RSA_RC4))
{
   // Print the Alg_Id returned in hex.
   printf("szOID_RSA_RC4 / %s is %x\n\n",szOID_RSA_RC4, Alg_Id);
}
else
{
   printf("No ALG_ID for OID szOID_RSA_RC4 / %s.\n", szOID_RSA_RC4);
}

//-------------------------------------------------------------------
// Convert the szOID_RSA_RC2CBC Object Identifier string to an 
// algorithm identifier.

if( Alg_Id = CertOIDToAlgId(szOID_RSA_RC2CBC))
{
   // Print the Alg_Id returned in hex.
   printf("szOID_RSA_RC2CBC / %s is %x\n\n",szOID_RSA_RC2CBC, 
      Alg_Id);
}
else
{
   printf("No ALG_ID for szOID_RSA_RC2CBC / %s.\n",szOID_RSA_RC2CBC);
}

//-------------------------------------------------------------------
// Convert the szOID_RSA_RC5_CBCPad Object Identifier string to an 
// algorithm identifier.

if( Alg_Id = CertOIDToAlgId(szOID_RSA_RC5_CBCPad))
{
   // Print the Alg_Id returned in hex.
   printf("szOID_RSA_RC5_CBCPad / %s is %x\n",szOID_RSA_RC5_CBCPad, 
      Alg_Id);
}
else
{
    printf("No ALG_ID for szOID_RSA_RC5_CBCPad: %s.\n",
      szOID_RSA_RC5_CBCPad);
}

//-------------------------------------------------------------------
// Initialize Int1 and Int2. 

Int1.pbData = (BYTE*)&BLOB1data;
Int2.pbData = (BYTE*)&BLOB2data;

//-------------------------------------------------------------------
// Set the cbData members so that only 
// the leftmost two bytes of the 
// first are compared to the leftmost bytes 
// of the second.

Int1.cbData = 4;  // sizeof(BLOB1data);
Int2.cbData = 2;  // sizeof(BLOB2data);

if( CertCompareIntegerBlob(
     &Int1, 
     &Int2))
{
   printf("The first two bytes of the BLOBs are identical.\n");
}
else
{
   printf("The first two bytes BLOBs are not identical.\n");
}

//-------------------------------------------------------------------
// Reset the cbData members to compare only 
// 1 byte from each.

Int1.cbData=1;
Int2.cbData=1;

if( CertCompareIntegerBlob(
       &Int1, 
       &Int2))
{
    printf("The BLOBs of different length are identical.\n");
}
else
{
    printf("The BLOBs of different length are not identical.\n");
}

//-------------------------------------------------------------------
// Reset to check the positive numbers.

Int1.cbData = 4;
Int2.cbData = 2;
Int1.pbData = BLOB3data;
Int2.pbData = BLOB4data;

if( CertCompareIntegerBlob(
       &Int1, 
       &Int2))
{
   printf("The BLOBs 3 and 4 are identical.\n");
}
else
{
   printf("The BLOBs 3 and 4 are not identical.\n");
}

//-------------------------------------------------------------------
// Compare BLOB 1 and BLOB 3.

Int1.cbData = 4;
Int2.cbData = 4;
Int1.pbData = BLOB1data;
Int2.pbData = BLOB3data;

if( CertCompareIntegerBlob(
       &Int1, 
       &Int2))
{
   printf("BLOBs 1 and 3 are identical.\n");
}
else
{
   printf("BLOBs 1 and 3 are not identical.\n");
}

//-------------------------------------------------------------------
// Compare BLOB 3 and BLOB 5.

Int1.cbData = 4;
Int2.cbData = 4;
Int1.pbData = BLOB5data;
Int2.pbData = BLOB3data;

if( CertCompareIntegerBlob(
       &Int1, 
       &Int2))
{
   printf("BLOBs 5 and 3 are identical.\n");
}
else
{
   printf("BLOBs 5 and 3 are not identical.\n");
}

//-------------------------------------------------------------------
// Compare the first two bytes of BLOB 3 and BLOB 5.

Int1.cbData = 2;
Int2.cbData = 2;
Int1.pbData = BLOB5data;
Int2.pbData = BLOB3data;

if( CertCompareIntegerBlob(
       &Int1, 
       &Int2))
{
   printf("The first two bytes of BLOBs 5 and 3 are identical.\n");
}
else
{
   printf("The first two bytes of BLOBs 5 and 3 not identical.\n");
}
} // end main

//-------------------------------------------------------------------
// Define the my_wait function.
void my_wait(char* s)
{
     printf(s);
     getchar();
}