RSA Signature/Verify with .key and .cer

Demonstrates how to use a .key file (private key) and digital certificate (.cer, public key) to create and verify an RSA signature.

Download 32-bit Chilkat RSA ActiveX (.msi)

Download All 32-bit Chilkat ActiveX Components (.zip)

Download All 64-bit Chilkat ActiveX Components (.zip)

CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @success int

    --  Load the private key from an RSA .key file:
    EXEC sp_OAMethod @privKey, 'LoadPemFile', @success OUT, 'privateKey.key'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    DECLARE @privKeyXml nvarchar(4000)

    --  Get the private key in XML format:
    EXEC sp_OAMethod @privKey, 'GetXml', @privKeyXml OUT

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

    --  Any string argument automatically begins the 30-day trial.

    EXEC sp_OAMethod @rsa, 'UnlockComponent', @success OUT, '30-day trial'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    --  Import the private key into the RSA component:
    EXEC sp_OAMethod @rsa, 'ImportPrivateKey', @success OUT, @privKeyXml
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    --  Create the signature as a hex string:
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'hex'

    --  If some other non-Chilkat application or web service is going to be verifying
    --  the signature, it is important to match the byte-ordering.
    --  The LittleEndian property may be set to 1
    --  for little-endian byte ordering,
    --  or 0  for big-endian byte ordering.
    --  Microsoft apps typically use little-endian, while
    --  OpenSSL and other services (such as Amazon CloudFront)
    --  use big-endian.
    EXEC sp_OASetProperty @rsa, 'LittleEndian', 0

    DECLARE @strData nvarchar(4000)

    SELECT @strData = 'This is the string to be signed.'

    --  Sign the string using the sha-1 hash algorithm.
    --  Other valid choices are "md2", "sha256", "sha384",
    --  "sha512", and "md5".
    DECLARE @hexSig nvarchar(4000)

    EXEC sp_OAMethod @rsa, 'SignStringENC', @hexSig OUT, @strData, 'sha-1'


    PRINT @hexSig

    --  Load a digital certificate from a .cer file:
    DECLARE @cert int
    EXEC @hr = sp_OACreate 'Chilkat.Cert', @cert OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OAMethod @cert, 'LoadFromFile', @success OUT, 'myCert.cer'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @cert, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    DECLARE @pubKey int

    EXEC sp_OAMethod @cert, 'ExportPublicKey', @pubKey OUT

    --  Now verify using a separate instance of the RSA object:
    DECLARE @rsa2 int
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa2 OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    --  Import the public key into the RSA object:
    EXEC sp_OAMethod @pubKey, 'GetXml', @sTmp0 OUT    EXEC sp_OAMethod @rsa2, 'ImportPublicKey', @success OUT, @sTmp0
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    --  The signature is a hex string, so make sure the EncodingMode is correct:
    EXEC sp_OASetProperty @rsa2, 'EncodingMode', 'hex'

    --  Verify the signature:
    EXEC sp_OAMethod @rsa2, 'VerifyStringENC', @success OUT, @strData, 'sha-1', @hexSig
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @rsa2, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        RETURN
      END

    PRINT 'Success.'
END
GO