(SQL Server) ECDSA Sign Data and Get Raw R and S Values

Demonstrates getting the raw R and S value of an ECDSA signature.

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
    DECLARE @iTmp0 int
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    -- This example requires the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    -- To create an ECDSA signature, the data first needs to be hashed.  Then the hash
    -- is signed.

    DECLARE @crypt int
    -- Use "Chilkat_9_5_0.Crypt2" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Crypt2', @crypt OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OASetProperty @crypt, 'HashAlgorithm', 'SHA256'
    EXEC sp_OASetProperty @crypt, 'Charset', 'utf-8'
    EXEC sp_OASetProperty @crypt, 'EncodingMode', 'base64'

    -- Hash a string.
    DECLARE @hash1 nvarchar(4000)
    EXEC sp_OAMethod @crypt, 'HashStringENC', @hash1 OUT, 'The quick brown fox jumps over the lazy dog'

    PRINT 'hash1 = ' + @hash1

    -- -----------------------------------------------------------
    -- An ECDSA private key is used for signing.  The public key is for signature verification.
    -- Load our ECC private key.
    -- Our private key file contains this:

    -- 	// -----BEGIN PRIVATE KEY-----
    -- 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
    -- 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
    -- 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
    -- 	-----END PRIVATE KEY-----

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

    DECLARE @success int
    EXEC sp_OAMethod @privKey, 'LoadPemFile', @success OUT, 'qa_data/ecc/secp256r1-key-pkcs8.pem'
    IF @success <> 1
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- Sign the hash..
    DECLARE @prng int
    -- Use "Chilkat_9_5_0.Prng" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Prng', @prng OUT

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

    DECLARE @ecdsaSigBase64 nvarchar(4000)
    EXEC sp_OAMethod @ecdsa, 'SignHashENC', @ecdsaSigBase64 OUT, @hash1, 'base64', @privKey, @prng
    EXEC sp_OAGetProperty @ecdsa, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 <> 1
      BEGIN
        EXEC sp_OAGetProperty @ecdsa, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @ecdsa
        RETURN
      END

    -- The ECDSA signature is ASN.1 that contains a sequence of 2 large integers (r and s)
    -- For example:
    -- SEQUENCE (2 elem)
    --   INTEGER (255 bit) 792134D9B4AD82D5431ED03835A88E2596EB35E5B13054BD9B05A0069281ACC9
    --   INTEGER (255 bit) 481E758CC1E3CBF825537EC3D9A2CA627E5FAD1137BBEA65DF38658DCB0A9ED5


    PRINT 'Base64 ECDSA signature = ' + @ecdsaSigBase64

    -- If the raw R and S values are needed, here's how to get them:
    DECLARE @asn int
    -- Use "Chilkat_9_5_0.Asn" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Asn', @asn OUT

    EXEC sp_OAMethod @asn, 'LoadEncoded', @success OUT, @ecdsaSigBase64, 'base64'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @asn, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @crypt
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @prng
        EXEC @hr = sp_OADestroy @ecdsa
        EXEC @hr = sp_OADestroy @asn
        RETURN
      END

    -- The R and X will be in hexidecimal in the XML.
    DECLARE @xml int
    -- Use "Chilkat_9_5_0.Xml" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.Xml', @xml OUT

    EXEC sp_OAMethod @asn, 'AsnToXml', @sTmp0 OUT
    EXEC sp_OAMethod @xml, 'LoadXml', @success OUT, @sTmp0
    EXEC sp_OAMethod @xml, 'GetXml', @sTmp0 OUT
    PRINT @sTmp0

    -- The XML looks like this:
    -- <sequence>
    -- <int>792134D9B4AD82D5431ED03835A88E2596EB35E5B13054BD9B05A0069281ACC9</int>
    -- <int>481E758CC1E3CBF825537EC3D9A2CA627E5FAD1137BBEA65DF38658DCB0A9ED5</int>
    -- </sequence>

    -- Copy raw R and S hex values into a Chilkat BinData object.
    DECLARE @bd int
    -- Use "Chilkat_9_5_0.BinData" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.BinData', @bd OUT

    DECLARE @r nvarchar(4000)
    EXEC sp_OAMethod @xml, 'GetChildContent', @r OUT, 'int[0]'
    DECLARE @s nvarchar(4000)
    EXEC sp_OAMethod @xml, 'GetChildContent', @s OUT, 'int[1]'
    EXEC sp_OAMethod @bd, 'AppendEncoded', @success OUT, @r, 'hex'
    EXEC sp_OAMethod @bd, 'AppendEncoded', @success OUT, @s, 'hex'


    EXEC sp_OAGetProperty @bd, 'NumBytes', @iTmp0 OUT
    PRINT 'Number of bytes in bd: ' + @iTmp0

    EXEC @hr = sp_OADestroy @crypt
    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @prng
    EXEC @hr = sp_OADestroy @ecdsa
    EXEC @hr = sp_OADestroy @asn
    EXEC @hr = sp_OADestroy @xml
    EXEC @hr = sp_OADestroy @bd


END
GO