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. 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
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    DECLARE @bd int
    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
        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
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    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
    EXEC @hr = sp_OACreate 'Chilkat.Rsa', @rsa OUT

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

    -- 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