/*

 File: CRAMMD5helper.c

 Abstract: Helper code for demonstration applications only

 Version: <1.0>

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple

 Computer, Inc. ("Apple") in consideration of your agreement to the

 following terms, and your use, installation, modification or

 redistribution of this Apple software constitutes acceptance of these

 terms.  If you do not agree with these terms, please do not use,

 install, modify or redistribute this Apple software.

 In consideration of your agreement to abide by the following terms, and

 subject to these terms, Apple grants you a personal, non-exclusive

 license, under Apple's copyrights in this original Apple software (the

 "Apple Software"), to use, reproduce, modify and redistribute the Apple

 Software, with or without modifications, in source and/or binary forms;

 provided that if you redistribute the Apple Software in its entirety and

 without modifications, you must retain this notice and the following

 text and disclaimers in all such redistributions of the Apple Software. 

 Neither the name, trademarks, service marks or logos of Apple Computer,

 Inc. may be used to endorse or promote products derived from the Apple

 Software without specific prior written permission from Apple.  Except

 as expressly stated in this notice, no other rights or licenses, express

 or implied, are granted by Apple herein, including but not limited to

 any patent rights that may be infringed by your derivative works or by

 other works in which the Apple Software may be incorporated.

 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE

 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION

 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS

 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND

 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL

 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF

 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS

 INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,

 MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED

 AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),

 STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE

 POSSIBILITY OF SUCH DAMAGE.

 Copyright © 2005 Apple Computer, Inc., All Rights Reserved

 */

#include "CRAMMD5helper.h"

#include <CommonCrypto/CommonDigest.h>

#include <strings.h>

void CalcMD5( const char *inChallenge, long inChallengeLen, const char *inPassword, long inPasswordLen, 

              unsigned char *outDigest )

{

    CC_MD5_CTX      md5Context;

    unsigned char   pInnerPad[65]   = { 0, };

    unsigned char   pOuterPad[65]   = { 0, };

    int             i;

    unsigned char   pTempKey[16];

    // if key is longer than 64 bytes reset it to key=MD5(key)

    if (inPasswordLen > 64) {

        CC_MD5_CTX      tempContext;

        CC_MD5_Init( &tempContext );

        CC_MD5_Update( &tempContext, inPassword, inPasswordLen );

        CC_MD5_Final( pTempKey, &tempContext );

        inPassword = pTempKey;

        inPasswordLen = 16;

    }

    bzero( pInnerPad, sizeof(pInnerPad) );

    bzero( pOuterPad, sizeof(pOuterPad) );

    bcopy( inPassword, pInnerPad, inPasswordLen );

    bcopy( inPassword, pOuterPad, inPasswordLen );

    // XOR key with ipad and opad values

    for (i=0; i<64; i++) {

        pInnerPad[i] ^= 0x36;

        pOuterPad[i] ^= 0x5c;

    }

    // perform the inner MD5

    CC_MD5_Init( &md5Context );

    CC_MD5_Update( &md5Context, pInnerPad, 64 );

    CC_MD5_Update( &md5Context, inChallenge, inChallengeLen );

    CC_MD5_Final( outDigest, &md5Context );

    // perform the outer MD5

    CC_MD5_Init( &md5Context );

    CC_MD5_Update( &md5Context, pOuterPad, 64 );

    CC_MD5_Update( &md5Context, outDigest, 16 );

    CC_MD5_Final( outDigest, &md5Context );

}