Installing R from CRAN Ubuntu repository: No Public Key Error - linux

Question

I am on R version 2.13 and would like to update to a newer version in order to use some packages that depend on R>= 2.14.
I have the line to my sources.list file as found described here. I then navigate to the terminal and type:
sudo apt-get update
and get the following error when trying to update R on the CRAN mirror closest to me:
Reading package lists... Done
W: GPG error: http://lib.stat.cmu.edu oneiric/ Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 51716619E084DAB9
Any idea how to debug this error?

Answer 1

The simplest solution that worked for me was from Emre Sahin in this thread:
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9

Answer 2

Like #Ben Bolker commented (sorry I hijacked your commented, but the correct answer was not yet posted), in the description of the debian package repo there is a section secure apt which says:
SECURE APT
The Debian backports archives on CRAN are signed with the key of
"Johannes Ranke (CRAN Debian archive) " with key
ID 381BA480. You can fetch this with
gpg --keyserver subkeys.pgp.net --recv-key 381BA480 or
alternatively, using another key server,
gpg --keyserver pgp.mit.edu --recv-key 381BA480 If this doesn't
work, it might be due to a firewall blocking port 11371.
Alternatively, you can search for 0x381BA480 at
http://keyserver.noreply.org/ or http://pgp.mit.edu/ and copy the key block into a plain text
file, named, for instance, jranke_cran.asc.
If receiving the key with gpg did work, you need to export it to a
text file
gpg -a --export 381BA480 > jranke_cran.asc In both cases you need
to make the key known to the apt system by running
apt-key add jranke_cran.asc as root.
If you have not already done this, this will probably fix your issue.

Answer 3

sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys KEYID
and replace KEYID with the number shown in the error message.

Answer 4

Thanks to Philipp Burckhardt, I got it fixed.
Try this:
gpg --keyserver pgpkeys.mit.edu --recv-key 51716619E084DAB9
gpg -a --export 51716619E084DAB9 | sudo apt-key add -

Answer 5

I encountered the same issue and the only solution I found, perhaps due to a firewall, was to use the helpful Y PPA Manager. The two steps below outline has worked on Ubuntu 15.04.
1) First install the Y PPA Manager:
sudo add-apt-repository ppa:webupd8team/y-ppa-manager
sudo apt-get update
sudo apt-get install y-ppa-manager
2) Then fetch missing keys by running the Y PPA Manager:
y-ppa-manager
Click "Advanced"
Next, click "Try to import missing GPG keys"
Finally, update again to check if it works:
sudo apt-get update

Answer 6

Here is a step-by-step answer that might be easier to follow.
Fetch the key (the last 8 digits in the warning message):
gpg --keyserver pgp.mit.edu --recv-key E084DAB9
The output should look like this:
gpg: requesting key E084DAB9 from hkp server pgp.mit.edu
gpg: key E084DAB9: public key "Michael Rutter <marutter#gmail.com>" imported
gpg: Total number processed: 1
gpg: imported: 1 (RSA: 1)
Add the key (superuser access required):
gpg -a --export E084DAB9 | sudo apt-key add -
Update the repositories:
sudo apt-get update
There should be no warning about the missing key now.

Answer 7

Much like others posted above, this one-liner seems to work well on Debian 6:
sudo apt-key adv --keyserver hkp://pgp.mit.edu:80 --recv-keys 381BA480
Executing: gpg --ignore-time-conflict --no-options
--no-default-keyring --secret-keyring /etc/apt/secring.gpg --trustdb-name /etc/apt/trustdb.gpg --keyring /etc/apt/trusted.gpg --primary-keyring /etc/apt/trusted.gpg --keyserver hkp://pgp.mit.edu:80 --recv-keys 381BA480
gpg: requesting key 381BA480 from hkp server pgp.mit.edu
gpg: key 381BA480: public key "Johannes Ranke (CRAN Debian archive) <jranke#uni-bremen.de>" imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg: imported: 1

Answer 8

This solved my problem
$ wget -q -O - https://archive.kali.org/archive-key.asc | apt-key add

Answer 9

It had to use a longer identifier for the key.
sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E298A3A825C0D65DFD57CBB651716619E084DAB9
The issue seems to be a duplicated key ID on the server.
See the instructions from the CRAN and more background info on this post by Michael Rutter.

Answer 10

The easiest fix is to simply follow the instructions from https://cran.r-project.org/bin/linux/ubuntu/. Run this as sudo:
# update indices
apt update -qq
# install two helper packages we need
apt install --no-install-recommends software-properties-common dirmngr
# add the signing key (by Michael Rutter) for these repos
# To verify key, run gpg --show-keys /etc/apt/trusted.gpg.d/cran_ubuntu_key.asc
# Fingerprint: 298A3A825C0D65DFD57CBB651716619E084DAB9
wget -qO- https://cloud.r-project.org/bin/linux/ubuntu/marutter_pubkey.asc | sudo tee -a /etc/apt/trusted.gpg.d/cran_ubuntu_key.asc
# add the R 4.0 repo from CRAN -- adjust 'focal' to 'groovy' or 'bionic' as needed
add-apt-repository "deb https://cloud.r-project.org/bin/linux/ubuntu $(lsb_release -cs)-cran40/"