Generate RSA Key and Sign a String

Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string.

Download Chilkat RSA Public-Key Encryption ActiveX

CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    DECLARE @sTmp0 nvarchar(4000)
    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.
    DECLARE @success int

    EXEC sp_OAMethod @rsa, 'UnlockComponent', @success OUT, '30-day trial'
    IF @success <> 1
      BEGIN
        PRINT 'RSA component unlock failed'
        RETURN
      END

    --  Generate a 1024-bit RSA key pair.
    EXEC sp_OAMethod @rsa, 'GenerateKey', NULL, 1024

    --  This example will sign a string, and receive the signature
    --  in a hex-encoded string.  Therefore, set the encoding mode
    --  to "hex":
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'hex'

    DECLARE @strData nvarchar(4000)

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

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

    EXEC sp_OAMethod @rsa, 'SignStringENC', @hexSig OUT, @strData, 'md5'


    PRINT @hexSig
    EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT

    PRINT @sTmp0

    --  Now verify the signature:
    EXEC sp_OAMethod @rsa, 'VerifyStringENC', @success OUT, @strData, 'md5', @hexSig
    IF @success = 1
      BEGIN
        PRINT 'Signature verified!'
      END
    ELSE
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT

        PRINT @sTmp0
      END

    --  Try it with an invalid signature:
    EXEC sp_OAMethod @rsa, 'VerifyStringENC', @success OUT, @strData, 'md5', 'not a valid sig'
    IF @success = 1
      BEGIN
        PRINT 'Signature verified!'
      END
    ELSE
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT

        PRINT @sTmp0
      END

    --  Try it with invalid data:
    EXEC sp_OAMethod @rsa, 'VerifyStringENC', @success OUT, 'Not the original data', 'md5', @hexSig
    IF @success = 1
      BEGIN
        PRINT 'Signature verified!'
      END
    ELSE
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT

        PRINT @sTmp0
      END

    --  Try it with the wrong hash algorithm:
    EXEC sp_OAMethod @rsa, 'VerifyStringENC', @success OUT, @strData, 'sha-1', @hexSig
    IF @success = 1
      BEGIN
        PRINT 'Signature verified!'
      END
    ELSE
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT

        PRINT @sTmp0
      END
END
GO