Uploaded March 2018 | Updated September 2026, 2 weeks ago
hackarcana.com ← check out my courses and CTF challenges
Connecting two computers using a soundcard
Spoiler: Near the beginning I make a stupid mistake of setting line-in echo playback thinking it's line-out volume. This eats away around 40 minutes near the 2 hour mark before Paweł (thanks!) points this out and everything magically starts working.
ToC (thx piomar123!):
12:48 Start
14:10 What to expect today
17:24 Updates:
21:40 Geneva Insomni'hack: https://insomnihack.ch/?page_id=16 ctftime.org/event/565
22:30 "Serious Cryptography" book
23:14 Today's Mission about blockchain
24:19 Questions
28:46 Soundcard networking hardware setup
36:27 Linux Amateur Radio AX.25: tldp.org/HOWTO/AX25-HOWTO/x495.html
39:48 Writing code
44:30 Bandwidth will be terrible
51:20 Synchronous vs. asynchronous protocols
53:35 Overview of our low-level protocol
1:07:16 10-bits encoding
1:32:05 Hi-pass filter problem
1:39:08 Decoding the received signal
2:31:06 The code that actually works with TCP tunnel (or does it? :D)
2:41:30 Questions
2:53:21 Problem fixed by Paweł Gomułka
3:01:32 Mission: goo.gl/VD3TtE
--- Links:
hackarcana.com ← my courses, articles, and CTF challenges
discord.gg/hackarcana ← hackArcana discord
https://gynvael.coldwind.pl/discord ← my / Paged Out! discord
https://pagedout.institute/ ← my Paged Out! magazine
https://gynvael.coldwind.pl/ ← my blog
https://bsky.app/profile/gynvael.bsky.social ← my Bluesky
--- Music in intro/outro:
TheFatRat - Monody feat. Laura Brehm
Watch the official music video: tinyurl.com/monodytfr
Listen to "Monody": thefatrat.ffm.to/monody
Follow TheFatRat: https://ffm.bio/thefatrat
nervous_testpilot - Office (Frozen Cortext Original Soundtrack)
nervous_testpilot - Our Heroes (Frozen Cortext Original Soundtrack)
nervous_testpilot - Focus (Frozen Synapse Original Soundtrack)
soundcloud.com/nervous_testpilot
nervoustestpilot.bandcamp.com
Stellardrone - Between the Rings
stellardrone.bandcamp.com/album/between-the-rings
soundcloud.com/stellardrone/between-the-rings
youtube.com/@StellardroneMusic
--- Team:
Shoutout and big thanks to my team who have helped me with livestreams and IRC/Discord over the years!
→ foxtrot_charlie
→ KrzaQ
→ masakra
→ hebi
→ maryush
→ disconnect3d
hackarcana.com ← check out my courses and CTF challenges
Connecting two computers using a soundcard
Spoiler: Near the beginning I make a stupid mistake of setting line-in echo playback thinking it's line-out volume. This eats away around 40 minutes near the 2 hour mark before Paweł (thanks!) points this out and everything magically starts working.
ToC (thx piomar123!):
12:48 Start
14:10 What to expect today
17:24 Updates:
21:40 Geneva Insomni'hack: https://insomnihack.ch/?page_id=16 ctftime.org/event/565
22:30 "Serious Cryptography" book
23:14 Today's Mission about blockchain
24:19 Questions
28:46 Soundcard networking hardware setup
36:27 Linux Amateur Radio AX.25: tldp.org/HOWTO/AX25-HOWTO/x495.html
39:48 Writing code
44:30 Bandwidth will be terrible
51:20 Synchronous vs. asynchronous protocols
53:35 Overview of our low-level protocol
1:07:16 10-bits encoding
1:32:05 Hi-pass filter problem
1:39:08 Decoding the received signal
2:31:06 The code that actually works with TCP tunnel (or does it? :D)
2:41:30 Questions
2:53:21 Problem fixed by Paweł Gomułka
3:01:32 Mission: goo.gl/VD3TtE
--- Links:
hackarcana.com ← my courses, articles, and CTF challenges
discord.gg/hackarcana ← hackArcana discord
https://gynvael.coldwind.pl/discord ← my / Paged Out! discord
https://pagedout.institute/ ← my Paged Out! magazine
https://gynvael.coldwind.pl/ ← my blog
https://bsky.app/profile/gynvael.bsky.social ← my Bluesky
--- Music in intro/outro:
TheFatRat - Monody feat. Laura Brehm
Watch the official music video: tinyurl.com/monodytfr
Listen to "Monody": thefatrat.ffm.to/monody
Follow TheFatRat: https://ffm.bio/thefatrat
nervous_testpilot - Office (Frozen Cortext Original Soundtrack)
nervous_testpilot - Our Heroes (Frozen Cortext Original Soundtrack)
nervous_testpilot - Focus (Frozen Synapse Original Soundtrack)
soundcloud.com/nervous_testpilot
nervoustestpilot.bandcamp.com
Stellardrone - Between the Rings
stellardrone.bandcamp.com/album/between-the-rings
soundcloud.com/stellardrone/between-the-rings
youtube.com/@StellardroneMusic
--- Team:
Shoutout and big thanks to my team who have helped me with livestreams and IRC/Discord over the years!
→ foxtrot_charlie
→ KrzaQ
→ masakra
→ hebi
→ maryush
→ disconnect3d
