SQL Server

RSA Signature using Private Key from .snk File

See more RSA Examples

A .snk file (Strong Name Key file) is a file format used in the .NET ecosystem to store an RSA public/private key pair. This key pair is typically used for strong-naming assemblies, which is a process of signing .NET assemblies to ensure their integrity and to uniquely identify them.

This example loads a private key from a .snk file and creates an RSA signature.

SQL Server

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @rsa int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- Load the .snk and return the private key as XML.
    DECLARE @xmlStr nvarchar(4000)
    EXEC sp_OAMethod @rsa, 'SnkToXml', @xmlStr OUT, './test.snk'
    EXEC sp_OAGetProperty @rsa, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rsa
        RETURN
      END

    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT

    EXEC sp_OAMethod @privKey, 'LoadXml', @success OUT, @xmlStr
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    EXEC sp_OAMethod @rsa, 'UsePrivateKey', @success OUT, @privKey
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
    -- Return the signature in base64 format.
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'base64'
    EXEC sp_OASetProperty @rsa, 'Charset', 'utf-8'
    DECLARE @sigBase64 nvarchar(4000)
    EXEC sp_OAMethod @rsa, 'SignStringENC', @sigBase64 OUT, 'This is the text to be hashed and signed.', 'sha256'
    EXEC sp_OAGetProperty @rsa, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @rsa
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END


    PRINT 'RSA signature as base64: ' + @sigBase64

    EXEC @hr = sp_OADestroy @rsa
    EXEC @hr = sp_OADestroy @privKey


END
GO