[NAHAMCONCTF] WhenAmI

Task source:

https://github.com/Tzion0/CTF/tree/master/NahamConCTF/2022/Miscellaneous/WhenAmI

Description

I know where I am, but… when am I?

This challenge provided a txt file.

Content of txt file:

When am I??

So, I look down at my watch. It's December 28, 2011 at 11:59AM, and I'm just minding my own business at -13.582075733990298, -172.5084838587106.
I hung out there until the local time was 1:00AM on December 31st, and then I hopped on a plane and took a 1 hour flight over to -14.327595989244111, -170.71287979386747.
Some time has passed since I landed, and on December 30th, 12PM local time, I took a 1 hour flight back to my original location.
It's been 10 hours since I landed on my most recent flight - how many seconds have passed since I first looked at my watch?

(Submission format is flag{<number of seconds goes here>}, such as flag{600}.)

This is quite a fun challenge, and I enjoy solving it.

Before we begin, let me convert those geographic coordinates into its places name:

-13.582075733990298, -172.5084838587106	 : "A'opo Conservation Area, Samoa"
-14.327595989244111, -170.71287979386747 : "Tualauta, Western District, American Samoa"

Google also shows that A’opo Conservation Area, Samoa is 24 hours ahead of Tualauta, Western District, American Samoa.

Now let’s start counting:

1 min + 12 hrs (29 December)
+ 24 hrs       (31 December)
+ 1 hr         (Because local time 1 AM)
+ 1 hr         (1 hour flight to Tualauta)
+ 10 hr        (Tualauta localtime December 30th, 12PM, which means "A'opo" is now December 31th, 12pm, and assuming "A'opo" was at 2 AM after arrived at Tualauta, so 12 - 2 = 10)
+ 1 hr 		   (1 hour flight back to "A'opo")
+ 10 hr    	   ("It's been 10 hours since I landed on my most recent flight")
+ 1 hr 		   (DST)

So, after 12 hrs and 1 min of 11:59 AM, December 28, 2011, we will enter 29 December, and after 24 hrs more we will be enter to 31 December. Why 31 instead of 30? Well, this is because Samoa changed its timezone on 2011, read more here: https://www.abc.net.au/news/2011-12-30/samoa-skips-friday-in-time-zone-change/3753350

After that, 1 hr for flight to Tualauta. After arriving Tualauta, A’opo localtime was December 31th, 2 AM while Tualauta was December 30th, 2 AM. And then at December 20th, 12 PM in Tualauta, he flight back to A’opo which means 12 - 2 = 10, so we need to add 10 hrs for that. Also don’t forget to add the 1 hr for the flight back to A’opo

Next, we need to add more 10 hrs as he said: “It’s been 10 hours since I landed on my most recent flight”

Lastly, we need to add more 1 hr because of Daylight Saving Time (DST) in Samoa 2011:

So the total is 60 hrs and 1 min = 216060 secs

Flag:

flag{216060}