(SQL Server) Verify an RSA Signature Against the Signed Hash

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the hash that was signed.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

-- Important: See this note about string length limitations for strings returned by sp_OAMethod calls.
--
CREATE PROCEDURE ChilkatSample
AS
BEGIN
    DECLARE @hr int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @bd int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bd OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    DECLARE @i int

    SELECT @i = 0
    WHILE @i <= 100
      BEGIN
        DECLARE @success int
        EXEC sp_OAMethod @bd, 'AppendEncoded', @success OUT, '000102030405060708090A0B0C0D0E0F', 'hex'
        SELECT @i = @i + 1
      END
    DECLARE @sha256_base64 nvarchar(4000)
    EXEC sp_OAMethod @bd, 'GetHash', @sha256_base64 OUT, 'sha256', 'base64'

    PRINT 'sha256 hash in base64 format: ' + @sha256_base64

    DECLARE @base64_rsa_sig nvarchar(4000)
    SELECT @base64_rsa_sig = 'AwF2BbOvL6jA5DwmMAc9n6J2Cc8PI6Rj5W079+aKJcIEtPWRzHor0Bvc3aftGM3Jbgj6SXlIC3M3RYS7UZOnfiHKFNZgbxaNT5WwsWooK42ZkC8DBZl0p7OunBUKd5SciUo+TKilioeUkriN3L1Zl9hwi3HVDVqgVo3XXskwIftSqLSFlepTLTmOWj9Y93dp8J4D9RyLtNgFQBc0WB22tyJTsuY56mLcWe1AMF3LizB9OrbwjynF2u16xWlrJdugccz795fJBUV9aQSD+8S3KeqwQhoi8RK1uhD68aGCyaSpBq0NZ8COAkn7MXaF4POxrAAt8udfHM+PRfSOptcH/w=='

    -- Get the public key to be used for signature verification.
    DECLARE @pubKey int
    -- Use "Chilkat_9_5_0.PublicKey" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    DECLARE @success int
    EXEC sp_OAMethod @pubKey, 'LoadFromFile', @success OUT, 'rsaKeys/chilkat-rsa-2048.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pubKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @bd
        EXEC @hr = sp_OADestroy @pubKey
        RETURN
      END

    DECLARE @rsa int
    -- Use "Chilkat_9_5_0.Rsa" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT

    EXEC sp_OAMethod @rsa, 'ImportPublicKeyObj', @success OUT, @pubKey

    -- Verify the hash against the signature.
    EXEC sp_OASetProperty @rsa, 'EncodingMode', 'base64'
    EXEC sp_OAMethod @rsa, 'VerifyHashENC', @success OUT, @sha256_base64, 'sha256', @base64_rsa_sig

    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @rsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0

        PRINT 'Signature invalid.'
      END
    ELSE
      BEGIN

        PRINT 'Signature valid.'
      END

    EXEC @hr = sp_OADestroy @bd
    EXEC @hr = sp_OADestroy @pubKey
    EXEC @hr = sp_OADestroy @rsa


END
GO