Using Ubuntu 14.04 LTS (64 bit).
$ sudo apt-get update
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.
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Fetched 2,079 kB in 1min 1s (33.7 kB/s)
Reading package lists... Done
W: GPG error: http://public-repo-1.hortonworks.com HDP InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B9733A7A07513CAD
W: GPG error: http://public-repo-1.hortonworks.com HDP-UTILS InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY B9733A7A07513CAD
How can I resolve this problem?