User`s manual

User’s Manual
134 Appendices
APPENDIX F: DIGIMUX DIGITAL SIGNATURES
The DigiMux provides the authentication of recorded video by means of a digital
signature scheme. For information on exporting the public key to an external device
as part of a digital signature, see
Export Digital Signature Key on page 91.
Your unit contains a unique public-private key pairs for digital signature verification.
The key pairs are already generated and stored in your DigiMux unit. The public key
is used to verify the digital signature. You can export the public key (
.gpg file) to an
external device any time using the menu system. For information on exporting the
public key to an external device as part of a digital signature, see
Export Digital
Signature Key on page 91. You may want to register your public key with a third party,
or deliver the public key to a third party, for future authentication of your recorded
video.
When you export video clips (.AVI files) with digital signature, the private key, which
is unknown to the public, is used to sign the clips and generate separate digital
signature files (
.sig files). After that, the signed clips and the signature files are
exported to an external device. The previously exported public key and the signature
files can then be used to verify the authenticity of the exported clips.
The following formula describes the sign/verify procedure:
signature = sign_function (video_clip, private_key);
verify = verify_function (signed_video_clip, signature, public_key);
Verifying the Digital Signature
To verify a digital signature, use the Gnu Privacy Guard program, named gpg.exe.
Following are the basic procedures for digital signature verification:
1. Create the following directory on your PC:
C:\gnupg
2. Copy the gpg.exe file, public key, exported clips, and signature files to this
directory.
3. Open a Command Prompt window on your PC and change to the C:\gnupg
directory by typing
C: <enter>
cd gnupg <enter>
where <enter> is the Enter key on your keyboard.
4. At the C:\gnupg prompt, enter the following command:
gpg --import public_key.gpg