OpenCSP开源程序解析之OPENCSP_Hash.cpp

#include ".\opencsp_hash.h"          //HASH函数主要用于完整性校验和提高数字签名的有效

OPENCSP_M$CSP* OPENCSP_Hash::_csp;
//hKey如果哈希算法是密钥哈希，如HMAC或MAC 算法，就用此密钥句柄传递密钥。对非密钥算法，此参数为NULL
OPENCSP_Hash::OPENCSP_Hash(ALG_ID Algid, HCRYPTKEY hKey, DWORD dwFlags)//Algid哈希算法的标示符
:_algId(Algid), _hKey(hKey), _dwFlags(dwFlags)
{
    _hHash = OPENCSP_Handle::getHandle();
    _csp = OPENCSP_M$CSP::createM$Instance();
    _csp->createHash(Algid, hKey, dwFlags, &_hHashInM$);
}

OPENCSP_Hash::~OPENCSP_Hash(void)
{
    _csp->destroyHash(_hHashInM$);
}
                                                            //Algid选择hash算法,phHash哈希对象的句柄
OPENCSP_Hash* OPENCSP_Hash::createHash(ALG_ID Algid, HCRYPTKEY hKey, DWORD dwFlags, HCRYPTHASH* phHash)
{                         // 此函数初始化哈希对象。它创建并返回了一个CSP哈希对象的句柄           
    OPENCSP_Hash* p = new OPENCSP_Hash(Algid, hKey, dwFlags);
    *phHash = p->getHashHandle();
    return p;
}

DWORD OPENCSP_Hash::getHashLen(DWORD& len) const      //获取哈希值长度
{
    DWORD ret = S_OK;  //返回正确

    switch(_algId)
    {
    case CALG_SSL3_SHAMD5:   //微软提供的算法
        len = 16 + 20;
        break;
    case CALG_MD5:        //微软提供的算法 
        len = 16;
        break;
    case CALG_SHA1:        //微软提供的算法    
        len = 20;
        break;
    default:
        ret = NTE_BAD_ALGID; //CSP不支持的算法
    }

    return ret;
}

DWORD OPENCSP_Hash::setHashValue(const BYTE* pbData, DWORD dwLen)//设置哈希值
{
    //设置哈希参数，pbData接收参数的缓冲区指针
    DWORD ret = _csp->setHashParam(_hHashInM$, HP_HASHVAL, pbData, 0); 
    if (ret != S_OK) return ret;
    return S_OK;
}

DWORD OPENCSP_Hash::getHashValue(HASH_VALUE& hv)      //获取哈希值
{
    BYTE bData[128] = {0};
    DWORD dwLen = 128;

    DWORD ret = _csp->getHashParam(_hHashInM$, HP_HASHVAL, bData, &dwLen, 0); // 获得Hash参数
    if (ret != S_OK) return ret;
    hv.insert(hv.end(), bData, bData + dwLen);
    return S_OK;
}

DWORD OPENCSP_Hash::feedHashData(const BYTE* pData, DWORD dataLen)  //往哈希句柄填充数据
{
    DWORD ret = _csp->hashData(_hHashInM$, pData, dataLen, 0);
    return ret;
}