Re: creating pkcs7 signature from large data

From: Vishal Agarwal[MSFT] (vishala_at_online.microsoft.com)
Date: 12/06/03 

Date: Fri, 5 Dec 2003 17:09:55 -0800

DWORD cbContentTotal = sizeof(pszContentTotal);

Should be

DWORD cbContentTotal = strlen(pszContentTotal);

Thanks,

Vishal[MSFT] 

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"G. Rodr?guez" <hez0s0@yahoo.com> wrote in message
news:96f084a3.0312011001.187bfcb7@posting.google.com...
> Hi, i've been using CAPICOM to build some S/MIME messages in p7
> format. However, CAPICOM seems to be unable to work with streaming,
> which makes it unacceptable to sign large amounts of data. So i moved
> to CryptoAPI, and tried to run some CAPI samples with streaming
> signatures. I finally made the sample to run with my smartcard, but
> the data i get does not seem to be valid ASN1 information. Such data
> is (b64-encoded):
>
MYHnMIHkAgEBMD4wNjELMAkGA1UEBhMCRVMxDTALBgNVBAoTBEZOTVQxGDAWBgNVBAsTD0ZOTVQg
Q2xhc2UgMiBDQQIEPHNZBjANBgkqhkiG9w0BAQUF
>
> I'd like to find a way to produce a message similar to CAPICOM
> SignedData.sign. I can't find my mistake in the following C CAPI code:
>
> void main(void){
>   char szContentTotal[] = "Se firmara este mensaje partido en dos
> trocitos.";
> char* pszContentTotal = szContentTotal;
> BYTE* pbContentTotal = (BYTE*) pszContentTotal;
> DWORD cbContentTotal = sizeof(pszContentTotal);
> char* pszProvider = "CeresCSP";
> HCRYPTPROV hCryptProv = NULL; // Handle returned here
> BOOL fReturn = FALSE;
> fReturn = CryptAcquireContext(&hCryptProv, NULL, pszProvider,
> PROV_RSA_FULL, 0 );
> if(!fReturn) {
> printf("CryptAcquireContext failed");
> return;
> }
>
> HCERTSTORE        hStoreHandle = NULL;
> hStoreHandle = CertOpenSystemStore(hCryptProv, "MY");
> if (!hStoreHandle) {
> printf( "Error Getting Store Handle");
> return;
> }
>
> PCCERT_CONTEXT    pSignerCert = NULL;
> pSignerCert = GetMySignerCert(hStoreHandle);
> if(!pSignerCert)
> {
> printf( "Error Getting Signer Cert");
> return;
> }
>
> DWORD                         HashAlgSize;
> CRYPT_ALGORITHM_IDENTIFIER    HashAlgorithm;
> HashAlgSize = sizeof(HashAlgorithm);
> memset(&HashAlgorithm, 0, HashAlgSize);
> HashAlgorithm.pszObjId = szOID_RSA_SHA1RSA;
>
> CMSG_SIGNER_ENCODE_INFO    SignerEncodeInfo;
> memset(&SignerEncodeInfo, 0, sizeof(CMSG_SIGNER_ENCODE_INFO));
> SignerEncodeInfo.cbSize = sizeof(CMSG_SIGNER_ENCODE_INFO);
> SignerEncodeInfo.pCertInfo = pSignerCert->pCertInfo;
> SignerEncodeInfo.hCryptProv = hCryptProv;
> SignerEncodeInfo.dwKeySpec = AT_SIGNATURE;
> SignerEncodeInfo.HashAlgorithm = HashAlgorithm;
> SignerEncodeInfo.pvHashAuxInfo = NULL;
>
> CMSG_SIGNER_ENCODE_INFO SignerEncodeInfoArray[1];
> SignerEncodeInfoArray[0] = SignerEncodeInfo;
>
> CERT_BLOB    SignerCertBlob;
> SignerCertBlob.cbData = pSignerCert->cbCertEncoded;
> SignerCertBlob.pbData = pSignerCert->pbCertEncoded;
>
> CERT_BLOB    SignerCertBlobArray[1];
> SignerCertBlobArray[0] = SignerCertBlob;
>
> CMSG_SIGNED_ENCODE_INFO SignedMsgEncodeInfo;
> memset(&SignedMsgEncodeInfo, 0, sizeof(CMSG_SIGNED_ENCODE_INFO));
> SignedMsgEncodeInfo.cbSize = sizeof(CMSG_SIGNED_ENCODE_INFO);
> SignedMsgEncodeInfo.cSigners = 1;
> SignedMsgEncodeInfo.rgSigners = SignerEncodeInfoArray;
> SignedMsgEncodeInfo.cCertEncoded = 1;
> SignedMsgEncodeInfo.rgCertEncoded = SignerCertBlobArray;
> SignedMsgEncodeInfo.rgCrlEncoded = NULL;
>
> DWORD        cbEncodedBlob;
> BYTE        *pbEncodedBlob = NULL;
>
> printf("Total size: %d\n", cbContentTotal);
> cbEncodedBlob = CryptMsgCalculateEncodedLength( PKCS_7_ASN_ENCODING,
>      // Msg encoding type
> 0,                      // Flags
> CMSG_SIGNED,            // Msg type
> &SignedMsgEncodeInfo,   // Ptr. to struct.
> NULL,                   // Inner content ObjID
> cbContentTotal);             // size of content
> if(0 == cbEncodedBlob) {
> printf("Getting cbEncodedBlob length failed\n");
> return;
> }else{
> printf("Se reservarán %d bytes\n", cbEncodedBlob);
> }
>
> pbEncodedBlob = (BYTE *) malloc(cbEncodedBlob);
> if(NULL == pbEncodedBlob) {
> printf("Malloc failed\n");
> return;
> }
>
> HCRYPTMSG    hMsg = NULL;
> CMSG_STREAM_INFO streamInfo;
> streamInfo.cbContent = cbContentTotal;
> streamInfo.pfnStreamOutput = CmsgStreamOutputCallback;
> streamInfo.pvArg = NULL;
> hMsg = CryptMsgOpenToEncode(
> PKCS_7_ASN_ENCODING,
> 0,
> CMSG_SIGNED,
> &SignedMsgEncodeInfo,
> szOID_RSA_data,
> &streamInfo);
>         if(NULL == hMsg) {
> printf("OpenToEncode failed\n");
> MyHandleError("Abriendo para codificar");
> free(pbEncodedBlob);
> return;
> }
>
> BOOL fResult;
> fResult = CryptMsgUpdate( hMsg, pbContentTotal, cbContentTotal,
> TRUE); if(!fResult){
> printf("MsgUpdate failed: %d\n", GetLastError());
> free(pbEncodedBlob);
> MyHandleError("Haciendo el update del MSG1");
> return;
> }
> CertFreeCertificateContext(pSignerCert);
> CertCloseStore(hStoreHandle, CERT_CLOSE_STORE_FORCE_FLAG);
> CryptMsgClose(hMsg);
> } //fin del main
>
> BOOL WINAPI CmsgStreamOutputCallback(IN const void *pvArg, IN BYTE
> *pbData, IN DWORD cbData, IN BOOL fFinal){
> if (fFinal){
> char *cResult = Encode64((char*) pbData);
> printf("Message encoded sucessfully: #%s#\n", cResult);
> }
> return TRUE;
> } //fin del CmsgStreamOutputCallback
>
>
> Thank you in advance.
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