RSA_ToXMLString creates an XML string representation of an RSA internal key string.
Public Declare Function RSA_ToXMLString Lib "diCrPKI.dll"
(ByVal strOutput As String, ByVal nOutChars As Long, ByVal strKeyString As String,
ByVal nOptions As Long) As Long
nRet = RSA_ToXMLString(strOutput, nOutChars,
strKeyString, nOptions) As Long
String to receive XML data.Long specifying the maximum number of characters to be received.String containing the RSA public or private key in internal formatLong option flags: Select and combine:RSAKeyValue for public key and RSAKeyPair for private key)RSAKeyValue formathexBinary format
long _stdcall RSA_ToXMLString(char *szOutput, long nOutChars, const char *szKeyString, long nOptions);
Long: If successful, the return value is the number of characters in the output string;
otherwise it returns a negative error code.
Call the function with a zero value of nOutChars to find out the required length of
the string. C/C++ users should add one to this value before allocating memory.
Both public and private key data can be output. The key must have been read first into an internal
key string using one of the other RSA key input functions in this toolkit.
If the internal key is a public key, or if the PKI_XML_EXCLPRIVATE option is used with a private key,
the output will always be a RSAKeyValue element
containing just <Modulus> and <Exponent> elements
as per [XMLSIG].
If the internal key is a private key and the PKI_XML_EXCLPRIVATE option is not used,
the default output will be a a XKMS-conforming RSAKeyPair element with the private key
parameters included. Including the PKI_XML_RSAKEYVALUE option will force a .NET-compatible
RSAKeyValue element instead.
The only difference between RSAKeyPair and RSAKeyValue is in the name of the
outer XML element. The default behaviour is to comply with the W3C standards
XKMS and [XMLSIG].
Users who wish to export a private key to use in the .NET world will
probably want to use the PKI_XML_RSAKEYVALUE option.
The PKI_XML_HEXBINARY option will output the binary data in hexBinary encoding format
instead of base64. This latter format is not in conformance with any W3C standard, but is provided to allow
users to see the data in more readable hex format. Such a format can be read by
this toolkit's RSA_FromXMLString function,
but don't try using it anywhere else.
This example reads in a private key from a encrypted private key file and then converts to an XML string in the .NET-compatible format.
Dim strEPKFile As String
Dim strPassword As String
Dim strPrivateKey As String
Dim strXML As String
Dim nLen As Long
strEPKFile = "AlicePrivRSASign.epk"
strPassword = "password"
' Read in the deciphered private key string in our internal format
strPrivateKey = rsaReadPrivateKey(strEPKFile, strPassword)
If Len(strPrivateKey) = 0 Then
MsgBox "Unable to retrieve private key"
Exit Function
End If
Debug.Print "INTKEY=" & strPrivateKey
' Convert to XML
nLen = RSA_ToXMLString("", 0, strPrivateKey, PKI_XML_RSAKEYVALUE)
' pre-dimension first
strXML = String(nLen, " ")
nLen = RSA_ToXMLString(strXML, Len(strXML), strPrivateKey, PKI_XML_RSAKEYVALUE)
strXML = Left(strXML, nLen)
Debug.Print "XML=" & strXML
The output should look like this (only longer):
INTKEY=MIICXAIBAAKBgQDgiXM5jdj19eiHdjl/ ... XML=<RSAKeyValue><Modulus>4IlzOY3Y9fXoh ... +yRRKt/IQ==</D></RSAKeyValue>