Problem installing Sodium package in R on an Ubuntu system

I am trying to install a package called sodium in R on an Ubuntu system but I'm getting an error message like the following:

install.packages("sodium", dependencies = T)

...

* installing *source* package ‘sodium’ ...
** package ‘sodium’ successfully unpacked and MD5 sums checked
Package libsodium was not found in the pkg-config search path.
Perhaps you should add the directory containing `libsodium.pc'
to the PKG_CONFIG_PATH environment variable
No package 'libsodium' found
Using PKG_CFLAGS=
Using PKG_LIBS=-lsodium
------------------------- ANTICONF ERROR ---------------------------
Configuration failed because libsodium was not found. Try installing:
 * deb: libsodium-dev (Debian, Ubuntu, etc)
 * rpm: libsodium-devel (Fedora, EPEL)
 * csw: libsodium_dev (Solaris)
 * brew: libsodium (OSX)
If libsodium is already installed, check that 'pkg-config' is in your
PATH and PKG_CONFIG_PATH contains a libsodium.pc file. If pkg-config
is unavailable you can set INCLUDE_DIR and LIB_DIR manually via:
R CMD INSTALL --configure-vars='INCLUDE_DIR=... LIB_DIR=...'
--------------------------------------------------------------------
ERROR: configuration failed for package ‘sodium’
* removing ‘/R/x86_64-pc-linux-gnu-library/3.4/sodium’
Warning in install.packages :
  installation of package ‘sodium’ had non-zero exit status

The downloaded source packages are in
    ‘/tmp/Rtmph70q7Q/downloaded_packages’

The following code didn't install it either.

install.packages("libsodium-dev", dependencies = T)

Warning in install.packages :
  package ‘libsodium-dev’ is not available (for R version 3.4.4)

I also tried install_github but still get an error:

devtools::install_github("jedisct1/libsodium")

Error: Failed to install 'unknown package' from GitHub:
  Timeout was reached: [api.github.com] Resolving timed out after 10000 milliseconds

Any idea on how to install this package?

I wish installing packages on an Ubuntu R was as error free as doing it on Windows R. If someone could teach me how to avoid package installing errors in Ubuntu R, it'd be great.

You need to install libsodium-dev, some software for your computer that isn't necessarily R specific.

You can do this via your terminal in linux. Go to your terminal and execute

sudo apt install libsodium-dev

Then go back to R and install the package with the usual command

devtools::install_github("jedisct1/libsodium")