DgsTSGetParam

The DgsTSGetParam function accepts an encoded TSTInfo and decodes the individual attributes.

DWORD DgsTSGetParam(
  BYTE *pbTSTInfo,        // in
  DWORD pcbTSTInfo,       // in
  DWORD dwParamType,      // in
  void *pvData,           // out
  DWORD *pcbData          // in/out

Parameters

pbTSTInfo

The encoded value of TSTInfo.  This is the eContent portion of EncapsulatedContentInfo.   Begins with the tag and length of the OCTET STRING.

If using the MicroSoft CryptoAPI then this is the handle to result of CryptMsgGetParam call using CMSG_CONTENT_PARAM.

pcbTSTInfo

The length of  pbTSTInfo

dwParamType

DWORD indicating the parameter types of data to be retrieved. The type of data to be retrieved determines the type of structure to use for pvData.

dwParamType value	Meaning	pvData type required
DGS_VERSION	The IETF specification version used to encode time stamp token.	The current release return 0.  Upon ratification, the server will be upgraded to version 1.
DGS_POLICY	Object identifier for TSA policy under which the time stamp was issued.	As of the time of writing, DigiStamp servers repond with policy 1.3.6.1.4.1.8291.1.1 This policy stipulates that the private key is not accessible to any party, the key is stored in NIST certified hardware (at minimum level 3), the time stamps are created inside this tamper detecting hardware and there is no log of created time stamps (you must store the resulting time stamp).
DGS_HASH_ALGORITHM	Retrieves the hash algorithm associated with the HASH that has been time-stamped	In this release this will always be the object identifier for SHA-1
DGS_HASH_ALGORITHM_PARAM	Retrieve the parameters used by the hash algorithm
DGS_HASH_DATA	Retrieves the hash value stored in the message when it was created.	A BYTE buffer to receive the hash value.
DGS_SERIAL_NUMBER	A unique serial number is part of each time stamp.	A BYTE buffer to receive the DER encoded value of the serial number. See function DgsDecInt to decode.
DGS_GENERALIZED_TIME	String representation of the GMT time of the time stamp creation.   In the form YYMMDDHHMMSSZ
DGS_ACCURACY_SECONDS	The potential time deviation from official time source.	seconds
DGS_ACCURACY_MILLIS	The potential time deviation from official time source in addition to the seconds.	milli seconds. Can be null.
DGS_ACCURACY_MICROS	The potential time deviation from official time source in addition to the seconds and milli seconds.	micro seconds. Can be null.
DGS_ORDERING	Indicates if the order of multiple time stamps can be determined the the time value in GENERALIZE_TIME	Set to false in this release. The SERIAL_NUMBER does provide ordering of time stamps.
DGS_NONCE	A random integer value supplied by the client to be incorporated into the time stamp. This current version of the C toolkit only supports up to 4 bytes (the Java version support full 20 byte nonce.)	A BYTE buffer to receive the DER encoded value of the nonce. See function DgsDecInt to decode.
DGS_TSA	Additional information, can provide means to contact TSA.	Always returns NULL in this release
DGS_EXTENSIONS	Additional information, can be used for future extensions to protocol.	Always returns NULL in this release

pvData

Pointer to a buffer that receives the data retrieved. The form of this data will vary, depending on the parameter type.  The caller of the function is responsible for deleting the memory allocated to hold this value.

When processing the data returned in this buffer, applications need to use the actual size of the data returned. The actual size can be slightly smaller than the size of the buffer specified on input. (On input, buffer sizes are usually specified large enough to ensure that the largest possible output data will fit in the buffer.) On output, the variable pointed to by this parameter is updated to reflect the actual size of the data copied to the buffer. If pvData is passed in as a NULL pointer then the function returns the size of buffer needed in the pcbData parameter. It's recommended that the caller program allocate a buffer of 64 bytes and reuse the same buffer to get different parameters.

pcbData

Pointer to a variable that specifies the size, in bytes, of the buffer pointed to by the pvData parameter. When the function returns, the variable pointed to by the pcbData parameter contains the number of bytes stored in the buffer.

Return Values

If the function succeeds, the return value is zero.  Return codes other that zero are describe below.  The numberical values are defined of the toolkit header files..

  10 October, 2000