OCSP_ReadResponse

CryptoSys PKI Pro Manual

OCSP_ReadResponse

Reads a response to an Online Certification Status Protocol (OCSP) request and outputs the main results in text form.

VBA/VB6 Syntax


Public Declare Function OCSP_ReadResponse Lib "diCrPKI.dll" (ByVal strOutput As String, ByVal nOutChars As Long, ByVal strResponseFile As String, ByVal strIssuerCert As String, ByVal strExtensions As String, ByVal nOptions As Long) As Long

nRet = OCSP_ReadResponse(strOutput, nOutChars, strResponseFile, strIssuerCert, strExtensions, nOptions)

C/C++ Syntax


long __stdcall OCSP_ReadResponse(char *szOutput, long nOutChars, const char *szResponseFile, const char *szIssuerCert, const char *szExtensions, long nOptions);

Parameters

szOutput: [out] to receive output as ordinary text.
nOutChars: [in] specifying the maximum number of characters to be received.
szResponseFile: [in] with the name of the file containing the response data in BER format.
szIssuerCert: [in] (optional) with name of issuer's X.509 certificate file (or base64 representation).
szExtensions: [in] Not used. Set as empty string "" or NULL.
nOptions: [in] Option flags. For future use. Specify zero.

Returns (VBA/C)

If successful, the return value is the number of characters in or required for the output string; otherwise it returns a negative error code.

VBA Wrapper Syntax

Public Function ocspReadResponse (szResponseFile As String, Optional szIssuerCert As String = "", Optional nOptions As Long = 0, Optional szExtensions As String = "") As String

.NET Equivalent

Ocsp.ReadResponse Method

C++ (STL) Equivalent

static std::string dipki::Ocsp::ReadResponse (const std::string &responseFile, const std::string &issuerCert="")

Python Equivalent

static Ocsp.read_response(responsefile, issuercert="")

Remarks

For the "raw" VBA/C function, the user must allocate an output string buffer szOutput of the required length. Specify a zero nOutChars or an empty string for szOutput to find the required length. ANSI C users must add one to this value when allocating memory.

The output is a text string outlining the main results in the response data. Typical result strings are:

Successful response:
 Produced at 2010-03-18T00:09:28Z
 CertStatus=good
 SerialNumber=00FBC723228C8C8022D8859223DEE70660

Successful response:
 Produced at 2010-03-27T12:13:11Z
 CertStatus=revoked at 2009-05-29T19:23:16Z
 SerialNumber=7FFED5D77FD1AEEC63716CA220B098A9

malformedRequest.

unauthorized.

Note that a revoked certificate will still result in a "Successful response".

The issuer's X.509 certficate szIssuerCert is optional. If provided, it will be used to check the signature on the OCSP reponse and and an error will result if the signature is not valid. CAUTION: For some CAs (e.g. VeriSign) the key used to sign the OCSP response is not the same as the key in the issuer's certificate, so specifying the issuer's certificate in this case will result in a signature error. If you can separately obtain the certificate used to sign the OCSP response, then specify this as the szIssuerCert; otherwise leave as the empty string "".

Example (VBA core function)

Dim nChars As Long
Dim strResponseFile As String
Dim strIssuerFile As String
Dim strBuf As String
strResponseFile = "ocsp_response_ok_dims.dat"
strIssuerFile = "UTNUSERFirst-Object.cer"
Debug.Print "ResponseFile=" & strResponseFile
Debug.Print "IssuerFile=" & strIssuerFile
nChars = OCSP_ReadResponse("", 0, strResponseFile, strIssuerFile, "", 0)
Debug.Print "OCSP_ReadResponse returns " & nChars & " (expected +ve)"
If (nChars <= 0) Then Exit Sub   ' ERROR
strBuf = String(nChars, " ")
nChars = OCSP_ReadResponse(strBuf, nChars, strResponseFile, strIssuerFile, "", 0)
Debug.Print "OCSPResponse=" & strBuf

The above example using a response received from ocsp.usertrust.com for our own (old but never revoked) code signing certificate produced the following output:

ResponseFile=ocsp_response_ok_dims.dat
IssuerFile=UTNUSERFirst-Object.cer
OCSP_ReadResponse returns 120 (expected +ve)
OCSPResponse=Successful response:
 Produced at 2010-03-18T00:09:28Z
 CertStatus=good
 SerialNumber=00FBC723228C8C8022D8859223DEE70660

Example (VBA wrapper function)

Dim strBuf As String
strBuf = ocspReadResponse("ocsp_response_ok_dims.dat", "UTNUSERFirst-Object.cer")
Debug.Print strBuf