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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for February 24th, 2022

Bash functions to encode and decode the ‘Basic’ HTTP Authentication Scheme

Posted by jpluimers on 2022/02/24

IoT devices still often use the ‘Basic’ HTTP Authentication Scheme for authorisation, see [Wayback] RFC7617: The ‘Basic’ HTTP Authentication Scheme (RFC ) and [Wayback] RFC2617: HTTP Authentication: Basic and Digest Access Authentication (RFC ).

Often this authentication is used even over http instead of over https, for instance the Egardia/Woonveilig alarm devices I wrote about yesterday at  Egardia/Woonveilig: some notes about logging on a local gateway to see more detailed information on the security system. This is contrary to guidance in:

  • RFC7617:
       This scheme is not considered to be a secure method of user
       authentication unless used in conjunction with some external secure
       system such as TLS (Transport Layer Security, [RFC5246]), as the
       user-id and password are passed over the network as cleartext.
  • RFC2617:
       "HTTP/1.0", includes the specification for a Basic Access
       Authentication scheme. This scheme is not considered to be a secure
       method of user authentication (unless used in conjunction with some
       external secure system such as SSL [5]), as the user name and
       password are passed over the network as cleartext.

Fiddling with those alarm devices, I wrote these two little bash functions (with a few notes) that work both on MacOS and in Linux:

# `base64 --decode` is platform neutral (as MacOS uses `-D` and Linux uses `-d`)
# `$1` is the encoded username:password
function decode_http_Basic_Authorization(){
  echo $1 | base64 --decode

# `base64` without parameters encodes
# `echo -n` does not output a new-line
# `$1` is the username; `$2` is the password
function encode_http_Basic_Authorization(){
  echo $1:$2 | base64

The first decodes the <credentials> from a Authorization: Basic <credentials> header into a username:password clean text followed by a newline.

The second one encodes a pair of username and password parameters into such a <credentials> string.

They are based on these initial posts that were not cross platform or explanatory:

  1. [Wayback] Decode HTTP Basic Access Authentication – Stack Pointer
  2. [Wayback] Create Authorization Basic Header | MJ’s Web Log


Posted in *nix, *nix-tools, Apple, Authentication, bash, bash, Communications Development, Development, HTTP, Internet protocol suite, Linux, Mac OS X / OS X / MacOS, Power User, Scripting, Security, Software Development, TCP, Web Development | Leave a Comment »

Days since last time zone issue

Posted by jpluimers on 2022/02/24

If you do business with for instance Jordan for he first time, then is likely -1 because tomorrow their clock moves forward one hour.

The 2022 daylight saving time changes (summer time / winter time) are at [Wayback/]

[] Dr. Jessie Christianstein 👩🏻‍🔬🧟‍♀️ on Twitter: “… “


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Posted in Algorithms, Development, Software Development | Leave a Comment »

Viewing the last lines of the postfix log with journalctl (with help from Unix & Linux Stack Exchange)

Posted by jpluimers on 2022/02/24

Two command-lines I use to view my Postfix logs:

  1. journalctl --unit postfix --since "2 days ago"
  2. journalctl --unit postfix --pager-end

Note that neither of these work well with the --follow (or equivalent -f) option, as this will effectively disable the pager (which by default is less).

The second is via [Wayback] systemd – How to see the latest x lines from systemctl service log – Unix & Linux Stack Exchange (which got the--pagerend bit wrong, as it misses a dash and should be --pager-end, but still thanks [Wayback] Daniel Kmak):


journalctl -u SERVICE_NAME -e

Parameter -e stands for:

-e –pagerend

That’s the one ! Other answers will go through the whole log to get to its end, which can be veeeeery long for large syslogs.

The last bit (by [Wayback] Léo Germond, thanks!) is why I like it most.

Similarly, specifying --since in the first example will not go through the whole log.

Some background information:

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Posted in *nix, *nix-tools, bash, Development, journalctl and journald, Linux, postfix, Power User, Scripting, Software Development, systemd | Leave a Comment »

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