Discuss this help topic in SecureBlackbox Forum

Encrypt a file with a password

Password-based encryption is a convenient way of exchanging information securely with someone who does not have an OpenPGP key pair. SecureBlackbox supports such encryption through a dedicated encryption mode of TElPGPWriter component.

1. To start with, create an instance of TElPGPWriter class:

   TElPGPWriter writer = new TElPGPWriter();
   

2. Set its EncryptionType property to TSBPGPEncryptionType.etPassphrase:

   pgpWriter.EncryptionType = SBPGP.TSBPGPEncryptionType.etPassphrase;
   

3. Add all the passwords you wish to be able to decrypt the protected object to the Passphrases list. You can add as many as you like:

   pgpWriter.Passphrases.Add("pa$$w0rd");
   pgpWriter.Passphrases.Add("qwerty");
   

4. Provide the source filename (doesn't need to be the real file name) and the encryption date:

   pgpWriter.Filename = "picture.jpg";
   pgpWriter.Timestamp = DateTime.UtcNow;
   

   Note: an empty string assigned to the Filename property will make the components create a for-your-eyes-only file, which won't be decrypted to a persistent media.
5. Tune-up encryption settings:

   pgpWriter.SymmetricKeyAlgorithm = SBPGPConstants.Unit.SB_PGP_ALGORITHM_SK_AES256;
   

   Note: in default configuration, TElPGPWriter comes with its own pre-defined encryption settings (CAST5 with 128 bit key, on the date of creation of this article).
6. Optionally tune-up supplementary options, such as armouring:

   pgpWriter.Armor = true;
   pgpWriter.Compress = true;
   

7. Call EncryptFile() method:

   pgpWriter.EncryptFile("picture.jpg", "picture.jpg.pgp");
   

How To articles about file encryption and signing with OpenPGP

Discuss this help topic in SecureBlackbox Forum