RSA_FromXMLString creates an RSA key string in internal format from an XML string.
Public Declare Function RSA_FromXMLString Lib "diCrPKI.dll"
(ByVal strOutput As String, ByVal nOutChars As Long, ByVal strXmlString As String,
ByVal nOptions As Long) As Long
nRet = RSA_FromXMLString(strOutput, nOutChars,
strXmlString, nOptions) As Long
String to receive key data either public or private.Long specifying the maximum number of characters to be received.String containing the RSA public or private key in XML formatLong option flags when the XML input data contains the private key:
long _stdcall RSA_FromXMLString(char *szOutput, long nOutChars, const char *szXmlString, long nOptions);
Long: If successful, the return value is the number of characters in the output string;
otherwise it returns a negative error code.
A key string created with this function can be used in the other RSA functions in this toolkit
that require a key in "internal" format.
Use this function to import an RSA key from another application.
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 when allocating memory.
Only US-ASCII characters are supported.
The XML data should be well formed and must contain either an
RSAKeyValue or RSAKeyPair element according to
[XMLSIG] or [XKMS2].
The parser has been designed to be pretty forgiving but don't push it too far.
The first such valid element found in the string will be converted and other data will be ignored.
If the XML data only contains the public key elements, the resulting internal string will contain a public key
and can be used in the functions in this toolkit that require a public key string.
If the XML data contains all the private key elements, the internal string will contain a private key
unless the PKI_XML_EXCLPRIVATE option is used.
To convert a private key, all components of the key pair must be present; namely,
the <Modulus>, <Exponent>,
<D>, <P>, <Q>, <DP>, <DQ>,
and <InverseQ> elements as specified in [XKMS2].
To allow compatibility with older versions of XKMS out there,
the deprecated elements <QINV>, <PublicExponent>
and <PrivateExponent> will be accepted.
To make life easier to import RSA key data that exists in hexadecimal format, the user can
force the function to decode the data in hexadecimal format instead of base64 by adding an attribute
with the value "hexBinary" to each of the component elements of the RSAKeyValue. For example
<Exponent EncodingType="hexBinary">010001</Exponent>
The attribute name is not important. This practice is not in conformance with any existing W3C standard (that we're aware of, anyway) but is included for convenience where the user is creating the XML file by hand using hex data.
This example converts an XML string into an internal public key that can be used in the other public key functions in this toolkit.
Dim strInternalKey As String
Dim strXML As String
Dim nLen As Long
Dim nRet As Long
strXML = "<RSAKeyValue>" _
& "<Modulus>CmZ5HcaYgWjeerd0Gbt/sMABxicQJwB1FClC4ZqNjFH" _
& "QU7PjeCod5dxa9OvplGgXARSh3+Z83Jqa9V1lViC7qw==</Modulus>" _
& "<Exponent>AQAB</Exponent>" _
& "</RSAKeyValue>"
nLen = RSA_FromXMLString("", 0, strXML, 0)
If nLen <= 0 Then
MsgBox ("Error: " & nLen)
Exit Function
End If
strInternalKey = String(nLen, " ")
nLen = RSA_FromXMLString(strInternalKey, Len(strInternalKey), strXML, 0)
strInternalKey = Left(strInternalKey, nLen)
Debug.Print "INTKEY=" & strInternalKey
nRet = RSA_CheckKey(strInternalKey, 0)
Debug.Print "RSA_CheckKey returns " & nRet
The second example is the same as the first except the XML data is in hexadecimal format.
Dim strInternalKey As String
Dim strXML As String
Dim nLen As Long
Dim nRet As Long
strXML = "<RSAKeyValue>" _
& "<Modulus EncodingType='hexBinary'>0A66791D" _
& "C6988168DE7AB77419BB7FB0C001C627102700751429" _
& "42E19A8D8C51D053B3E3782A1DE5DC5AF4EBE9946817" _
& "0114A1DFE67CDC9A9AF55D655620BBAB</Modulus>" _
& "<Exponent EncodingType='hexBinary'>010001</Exponent>" _
& "</RSAKeyValue>"
nLen = RSA_FromXMLString("", 0, strXML, 0)
If nLen <= 0 Then
MsgBox ("Error: " & nLen)
Exit Function
End If
strInternalKey = String(nLen, " ")
nLen = RSA_FromXMLString(strInternalKey, Len(strInternalKey), strXML, 0)
strInternalKey = Left(strInternalKey, nLen)
Debug.Print "INTKEY=" & strInternalKey
nRet = RSA_CheckKey(strInternalKey, 0)
Debug.Print "RSA_CheckKey returns " & nRet
Both examples should produce the output (shortened here):
INTKEY=MEcCQApmeR3...yamvVdZVYgu6sCAwEAAQ== RSA_CheckKey returns 1