SQL Server

Export an Encrypted PKCS #8 Private Key as PEM

Demonstrates the Chilkat PrivateKey.GetPkcs8EncryptedPem method, which exports the key as password-protected PKCS #8 PEM (-----BEGIN ENCRYPTED PRIVATE KEY-----). The only argument is the password; the cipher is selected by the Pkcs8EncryptAlg property.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the safe way to export a key for storage or transfer — the private material is encrypted under a passphrase, so a leaked file is not immediately usable. It is the format to reach for whenever a key leaves your process. Control the encryption cipher with Pkcs8EncryptAlg, and source the password securely rather than hard-coding it.

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-- 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
    DECLARE @sTmp0 nvarchar(4000)
    DECLARE @success int
    SELECT @success = 0

    --  Load a private key to export.
    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/private.pem'
    IF @success = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    --  The key password is not hard-coded in a real application; obtain it from an interactive
    --  prompt, environment variable, or a secrets vault.
    DECLARE @password nvarchar(4000)
    SELECT @password = 'myKeyPassword'

    --  Export as password-protected PKCS #8 PEM ("-----BEGIN ENCRYPTED PRIVATE KEY-----").  The
    --  encryption cipher is selected by the Pkcs8EncryptAlg property.
    DECLARE @pem nvarchar(4000)
    EXEC sp_OAMethod @privKey, 'GetPkcs8EncryptedPem', @pem OUT, @password
    EXEC sp_OAGetProperty @privKey, 'LastMethodSuccess', @iTmp0 OUT
    IF @iTmp0 = 0
      BEGIN
        EXEC sp_OAGetProperty @privKey, 'LastErrorText', @sTmp0 OUT
        PRINT @sTmp0
        EXEC @hr = sp_OADestroy @privKey
        RETURN
      END

    PRINT @pem

    EXEC @hr = sp_OADestroy @privKey


END
GO