Black Mesa:Timeline

Many thanks to /u/pieter888 for their excellent reddit posts covering the progress in the ARG. Also, huge thanks to /u/Lucario995 and Discord user Q101 for their fantastic docs covering the tweet and message translations!

The Organisations Atwitter

Aperture Science

@ApertureSciInc, related to the organization of the same name from the Portal series, has existed as far back as 2016-03-28.

Black Mesa Research Facility

The more interesting @BlackMesaRF, related to the organization of the same name from the Half-Life series, has existed as far back as 2016-03-13. It has a pinned tweet promising to answer all questions asked to it, and although this is not quite true, many questions have been answered in this way.

X

VHJhaWxoZWFk

On 2016-04-11, @BlackMesaRF tweeted the following messages:

signalinterrupted

prepareforunforseencircumstances

QGNvbnhhY3Q=

This last tweet turned out to be valid Base64, and was solved by /u/pieter888. The tweet decoded to "@conxact," leading to a third Twitter account.

All Your Base64 Are Belong To Us

@conxact continued to post similar tweets, some with no encryption and others using Base64 or ASCII85, from 2016-04-12. These tweets and their conversions are covered on the Archives page. Only tweets relevant to the progression of the ARG will be covered here.

On 2016-04-25, @conxact tweeted this, using the ASCII85/qwerty method of enciphering;

<~0R6AdAP-re=(k;g3)OWn~>

This decoded to 0yMLeJqxWhM98QpS, which was actually the code for a Discord server entitled xxxxxx.

Discordant

The Discord user xxxxx joined the server between 2016-04-26 and 2016-04-28 to chat. Initially, this was in ASCII85, but this later changed to plain text. Conversations with @conxact and @ApertureSciInc also happened. All these conversations are covered on the archive page.

On 2016-05-01, xxxxx returned to the server and gave the following message, which is yet to be deciphered:

u lC rraha enafsqsntku.geii erlrI le ia mnlsya leoyp.t

A clue was later given as an @conxact tweet which converted to 5 3 and translated to te:

<~2'=[~>

A few questions were answered by xxxxx on Discord, with this piece of information also given:

If you cannot solve that small puzzle, then the message itself will become irrelevant.

Aperture Science advised this: A coworker of mine has told me that it looks like a strange version of the 'bible code', if that helps. Another tweet was later tweeted by @conxact, converting to begin after 3:

<~@V'1dDBNA"FCfJ81B~> This was followed by yet another, this time deciphering to every fifth:

<~AThX*Gp$5Aoq~> The puzzle was eventually solved by Discord users carnifex, whizzer0, and butterfingerbatman by taking every fifth character after the third character:

Change in plans. I may require your skill set after all.

This led to another set of messages:

<~CLqc62(O@~>

<~;gMkuH$F@KFCB30@;K@`@VKG!Dg?A9EHHAJA9;9lG@G30~>

<~7ri<S~>

These decoded to key 5-16, Szazyxrptarqalaebifxoyrgqtvwdtbewbgx, and grid respectively. Szazyxrptarqalaebifxoyrgqtvwdtbewbgx was decoded in a Bifid cipher with the key maysixten, giving us:

Your services will be invaluable in the war Later that evening, another code was given:

<~=`>KpDf'MI8TJlpBl>UHE-!-EFtR3?ART.aB5M?nEc*!P~>

This was decoded as a 6-rail railfence, decoding to:

You are improving... I am impressed. Three days later, another message arrived:

<[email protected]>IkHG]nMH".t;GA1NDJa,@~>

This message was a Keyed Vigenere cipher, with passkey of FINAL and alphabet of MESABCDFGHIJKLNOPQRTUVWXYZ, which decoded as:

Your training is complete.