it’s weird how “taking the train to berlin from prague” has become a non-exotic behavior i don’t feel like a foreigner or a tourist. i feel more endemic, like a person with connection to the place and business being here

there’s a lot of talk about “covenants” but not a lot of understanding what that entails. lets do a little dive into how i think about the opcode proposals and how they relate to “enabling covenants on bitcoin” what is a covenant? great question. a covenant is the ability to specify what the transaction that spends your bitcoin must look like. for example, you could say “the transaction that spends this bitcoin must pay 500k sats to this address” or “the transaction that spends this bitcoin must have a locktime set to block 880,000” in order to make these kinds of assertions in bitcoin transactions, you need the ability to find out what information is in the transaction that is spending an output. this information needs to be accessible when the script is running. bitcoin script is a limited programming language that you use to write locks for bitcoin. one of the limitations is what data you have access to while the program is running. so in order to write more “expressive” bitcoin scripts, which can say “one output must be to my address and pay 500k sats”, for example, you need to be able to look at the outputs on a transaction. this ability to look at the info on a transaction is called “introspection”. being able to introspect a transaction is a big missing piece in bitcoin. adding introspection enables you to write covenants. so how do you get introspection in bitcoin script? you have to add a new opcode for it. in fact, we’ve added two opcodes to bitcoin that enable introspection already: op-checklocktimeverify (op-cltv) and op-checksequenceverify (op-csv) these look at the locktime/sequence of a transaction and require a certain value to be set in order to be valid. they were added in order to enable lightning, which uses both op-cltv and op-csv to make “primitive” covenants. these were added to enable LN, to help scale bitcoin. today you could write a bitcoin script that asserts “the transaction that spends this bitcoin must have a locktime set to block 880,000”. you’d use op-cltv to make that script, and any coins locked to that script wouldn’t be spendable til block 880,000. there’s no way to look at the output fields in a transaction though. you cant write a script that requires funds to go somewhere, you’d have to use presigned txs (like how lightning does) to make that kind of assertion. ok so the goal of introspection is to let you look at what information is in a transaction that’s spending a bitcoin output. we can do this already with op-cltv and op-csv. but this is limited just to timelocks, and doesn’t let us make assertions about outputs, or other inputs. in the next post i’ll talk about how the current opcode proposals (op-ctv, op-txhash, op-tx, op-cat) work and how they enable more broad tx introspection ! if you found this interesting, check out @Base58⛓🔓 and our classes on bitcoin transactions!

thought my train left at 5p; got to the station at 4.12p. couldn’t find my train on the board, no luck finding my ticket in my email. checked the train ticketing app, next train is at 4.28p. yep, i can definitely see that train on the board. it’s now 4.16p. i smash buy a ticket on the app and start looking for the track but cant find it. head to the information desk, ask where the track is. turns out it’s all the way at the end if the station on the second floor. it’s now 4.21p. i run. make it to the platform, there’s a big flight of stairs up. I have 100lbs of luggage, there’s no time to look for an elevator so i start dragging. I make it to the platform. it’s now 4.26p. the train is still there. I head to the nearest door and climb on. ive been on this route before and know that the regular fare cars always get overbooked. you end up spending the 4 and a half hour ride sitting in the aisle. i paid extra for a first class ticket so i could avoid this fate (and tried to arrive forty minutes early rip) problem is, i have no idea where the first class car is. im stuck in the middle of the train. the aisles are crowded. I’m dragging two oversize suitcases. i start walking towards the front of the train but it’s ugly. the aisles are strewn with people who are hunkering down for a long ride. they are very much unhappy about me pushing past them. i feel bad but at this point i have paid for not one but two tickets on this train. i am getting to the first class car, preferably before we get to the next station and more people board. it’s insane to me that the tickets are sold without reservations, this whole situation feels extremely chaotic. sure it’s partly my fault, it’s also completely nuts to me how oversold trains here are. i only have to walk through three cars to get to the first class car. it’s also packed but there’s no one in the aisle and there is one empty seat next to a sleeping lady. i wake her up to so she’ll move her stuff off the unoccupied seat. there’s even a luggage rack on this car, what a luxury. luggage stowed, seat acquired, and we’re on the way to Berlin 🙌 🇨🇿 🚆🇩🇪

gm day 2 in #prague was another day with the hacker community at #paralelnípolis #hcpp #traveltok

the core lightning telegram reached over 1k members!!

i picked up a really amazing wool skirt in kyoto and have been so grateful for it in the chilly weather here in prague. walking around, i noticed lots of ladies looking a tad chilly in pants and it sorta occurred to me that traditional “women’s clothes” are a lot cozier in colder weather than pants are i used to wear two pairs of pants from October to April when i lived in NYC. kinda funny to realize i probably would have been much happier in long wool skirts women get cold more easily, makes sense that we’d have “blankets that attach to your body” as a fashion statement before central heating existed 🤣

gm we made it to #prague for #hcpp the yearly Hacker’s Congress at Paralelní Polis #traveltok ✈️

day 15 in #japan is the last, mostly just hung out in trains and planes ✈️ 🚊 #traveltok #doha #eurotrip

starting to suspect not being addicted to caffeine is actually a competitive advantage for jetlag

shanghai at night from 32k feet

whatever people say about losing weight in europe has definitely not happened to me in japan fwiw, despite hiking for a few hours almost every day

gm day 14 of #japan and i got surprised by a shrine visit bait and switch (9,999 torii gates to heaven?) #kyoto #traveltok

getting my #fortune at #inari temple in #kyoto #japan #12

ok ok maybe the only research i did before getting to japan was on steel making and hot baths. and i haven’t seen any knives (yet) 😂 View quoted note →

why did no one tell me the red torii instagram gates are on a trail that’s 2km of ~straight up 😂

welcome to day 2 in #kyoto/day 13 in #japan, mostly eating food and shopping at #takashimaya an enormous department store in kyoto while trying to manage a bad sinus headache 😭 #traveltok

new substack post!

Nifty no Japan

Sept 14 - Sept 27

endlessly impressed that kanji writing systems actually work

every once in a while i remember im responsible for making things happen and i pull out a sheet of paper to write a “to do list”

first @Base58⛓🔓 workshop in Japan 🇯🇵 feat @niftynei() 🇺🇸💸🧡 and @npub1cpzp...sfvr