(SQL Server) Get EC Public Key from EC Private Key

Demonstrates how to get an EC public key from an EC private key.

Note: This example requires Chilkat v11.0.0 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
    -- Important: Do not use nvarchar(max).  See the warning about using nvarchar(max).
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    -- We have an ECC private key...
    -- The contents of the private key PEM file look like this:

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

    DECLARE @privKey int
    EXEC @hr = sp_OACreate 'Chilkat.PrivateKey', @privKey OUT
    IF @hr <> 0
    BEGIN
        PRINT 'Failed to create ActiveX component'
        RETURN
    END

    EXEC sp_OAMethod @privKey, 'LoadPemFile', @success OUT, 'qa_data/ecc/secp256r1-key-pkcs8.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    -- Get the public key.
    DECLARE @pubKey int
    EXEC @hr = sp_OACreate 'Chilkat.PublicKey', @pubKey OUT

    EXEC sp_OAMethod @privKey, 'ToPublicKey', @success OUT, @pubKey

    -- Save the public key to a PEM file.
    EXEC sp_OAMethod @pubKey, 'SavePemFile', @success OUT, 0, 'qa_data/ecc/secp256r1-pubkey.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @pubKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        EXEC @hr = sp_OADestroy @pubKey
        RETURN
      END

    -- The contents of the ECC public key PEM file look like this:

    -- 	-----BEGIN PUBLIC KEY-----
    -- 	MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
    -- 	AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
    -- 	///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
    -- 	NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
    -- 	RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
    -- 	//////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABOVKaiLPKEDChhkA64UEBOXT
    -- 	v/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=
    -- 	-----END PUBLIC KEY-----


    PRINT 'Success.'

    EXEC @hr = sp_OADestroy @privKey
    EXEC @hr = sp_OADestroy @pubKey


END
GO