mc_md5.h File Reference

Detailed Description

This simple MD5 implementation is derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm and modified slightly to be functionally identical but condensed into control structures.

All functions provided by this module require a structure McMD5Context_s to store an intermediate hash value as well as the MD5 result (digest). The structure has to be initialized by McMD5Init(). The MD5 checksum is computed by calling McMD5Add() and McMD5Finalize().

#include "md5.h"
..
int32_t computeMd5()
{
   char              szBufferT[40];
   char              szInputT[] = "Hello";
   int32_t           slResultT;
   McMD5Context_ts   tsMD5ContextT;
 
   //---------------------------------------------------------------------------------------------------
   // MD5 checksum on "Hello, World!", input is added in 3 parts   
   //
   McMD5Init(&tsMD5ContextT);
 
   McMD5Add(&tsMD5ContextT, (uint8_t *) szInputT, strlen(szInputT));
 
   strcpy(szInputT, ", W");
   McMD5Add(&tsMD5ContextT, (uint8_t *) szInputT, strlen(szInputT));
 
   strcpy(szInputT, "orld!");
   McMD5Add(&tsMD5ContextT, (uint8_t *) szInputT, strlen(szInputT));
 
   McMD5Finalize(&tsMD5ContextT);
 
   //---------------------------------------------------------------------------------------------------
   // MD5 checksum of "Hello, World!" input: 65a8e27d8879283831b664bd8b7f0ad4
   //
   McMD5String(&tsMD5ContextT, &szBufferT[0], false);
   printf("Checksum %s \n", szBufferT);
   slResultT = strcmp(&szBufferT[0], "65a8e27d8879283831b664bd8b7f0ad4");
   
   return (slResultT);
}

The output of this code example is:

Checksum 65a8e27d8879283831b664bd8b7f0ad4 

Include dependency graph for mc_md5.h:

Data Structures
struct	McMD5Context_s

Functions
void	McMD5Add (McMD5Context_ts *ptsMd5ContextV, uint8_t *pubInputV, uint32_t ulInputSizeV)
void	McMD5Finalize (McMD5Context_ts *ptsMd5ContextV)
void	McMD5Init (McMD5Context_ts *ptsMd5ContextV)
void	McMD5String (McMD5Context_ts *ptsMd5ContextV, char *pszBufferV, bool_t btUpperCaseV)

Function Documentation

McMD5Add()

void McMD5Add	(	McMD5Context_ts *	ptsMd5ContextV,
		uint8_t *	pubInputV,
		uint32_t	ulInputSizeV )

Parameters

[in]	ptsMd5ContextV	Pointer to MD5 context structure
[in]	pubInputV	Pointer to input data
[in]	ulInputSizeV	Size of input data in bytes

See also

McMD5Finalize()

The function adds input data to the context MD5 context structure defined by ptsMd5ContextV. The size of the input data in bytes is defined by parameter ulInputSizeV.

If the input fills out a block of 512 bits, the internal MD5 algorithm is applied and the result in stored in the buffer of the MD5 context structure. The function also updates the overall size inside the context structure defined by ptsMd5ContextV.

McMD5Finalize()

void McMD5Finalize

(

McMD5Context_ts *

ptsMd5ContextV

)

Parameters

[in]

ptsMd5ContextV

Pointer to MD5 context structure

See also

McMD5Add()

The function pads the current input which has been applied by McMD5Add() to get to 448 bytes. The result of the final iteration is saved into the digest of the MD5 context structure (McMD5Context_ts::aubDigest). The binary MD5 checksum can be retrieved by reading the digest array. As alternative it is possible to convert the MD5 checksum into a character string by calling McMD5String().

McMD5Init()

void McMD5Init

(

McMD5Context_ts *

ptsMd5ContextV

)

Parameters

[in]

ptsMd5ContextV

Pointer to MD5 context structure

The function initializes the MD5 context structure defined by ptsMd5ContextV for further operation.

McMD5String()

void McMD5String	(	McMD5Context_ts *	ptsMd5ContextV,
		char *	pszBufferV,
		bool_t	btUpperCaseV )

Parameters

[in]	ptsMd5ContextV	Pointer to MD5 context structure
[in]	pszBufferV	Pointer to string buffer
[in]	btUpperCaseV	Flag for upper-case character output

The function prints the digest (MD5 checksum) of the MD5 context structure defined by ptsMd5ContextV to the character buffer pszBufferV. The size of the buffer must be at least 33 bytes. By parameter btUpperCaseV the output string can be controlled between lower-case and upper-case character.

#include "md5.h"
..
int32_t printChecksum()
{
   char              szBufferT[40];
   McMD5Context_ts   tsMD5ContextT;
 
   //---------------------------------------------------------------------------------------------------
   // MD5 checksum of empty input
   //
   McMD5Init(&tsMD5ContextT);
 
   McMD5Add(&tsMD5ContextT, CPP_NULL, 0);
   McMD5Finalize(&tsMD5ContextT);
 
   //---------------------------------------------------------------------------------------------------
   // MD5 checksum of empty input: 
   //
   McMD5String(&tsMD5ContextT, &szBufferT[0], false);
   printf("Checksum lower-case: %s \n", szBufferT);
 
   McMD5String(&tsMD5ContextT, &szBufferT[0], true);
   printf("Checksum upper-case: %s \n", szBufferT);
   
}

The output of this code example is:

Checksum lower-case: d41d8cd98f00b204e9800998ecf8427e 
Checksum upper-case: D41D8CD98F00B204E9800998ECF8427E