You can verify packages replicated on SIVACOR using the following GPG key:
-----BEGIN PGP PUBLIC KEY BLOCK-----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=Mfz0
-----END PGP PUBLIC KEY BLOCK-----
also available at Ubuntu - OpenPGP Keyserver.