(SQL Server) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

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 assumes the Chilkat API to have been previously unlocked.
    -- See Global Unlock Sample for sample code.

    -- Load an EC key from some format..
    DECLARE @privKey int
    -- Use "Chilkat_9_5_0.PrivateKey" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    -- This loads an ECDSA key from an unencrypted PEM file (no password required).
    DECLARE @success int
    EXEC sp_OAMethod @privKey, 'LoadAnyFormatFile', @success OUT, 'qa_data/ecc/openssl_ecc_privKey.pem', ''
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- The key type should be "ecc" to indicate an EC key.

    EXEC sp_OAGetProperty @privKey, 'KeyType', @sTmp0 OUT
    PRINT 'key type = ' + @sTmp0

    -- What is the size of the private key in bits?

    EXEC sp_OAGetProperty @privKey, 'BitLength', @iTmp0 OUT
    PRINT 'size in bits = ' + @iTmp0

    -- Get the private and public EC key parts in raw hex format:
    DECLARE @sbPubKeyHex int
    -- Use "Chilkat_9_5_0.StringBuilder" for versions of Chilkat < 10.0.0
    EXEC @hr = sp_OACreate 'Chilkat.StringBuilder', @sbPubKeyHex OUT

    DECLARE @privKeyHex nvarchar(4000)
    EXEC sp_OAMethod @privKey, 'GetRawHex', @privKeyHex OUT, @sbPubKeyHex

    -- If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).

    PRINT 'private key = ' + @privKeyHex

    -- The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)

    EXEC sp_OAMethod @sbPubKeyHex, 'GetAsString', @sTmp0 OUT
    PRINT 'public key = ' + @sTmp0

    -- Sample output:
    -- key type = ecc
    -- size in bits = 256
    -- private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
    -- public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a

    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @sbPubKeyHex


END
GO