robwoodgate
Rob Woodgate

v4.11.0 of Cashu-TS. the library behind many Cashu wallets, is now available. This release has numerous fixes, including websocket close callback, default request timeout and better NUT-19 retry handling.
This stable release v4 is recommended for all production wallets.
We also have v5.0.0-RC.11 release candidate which implements the experimental "Nutroot" and "keyset v3" (BLS). Testing is welcomed, but be aware that spec changes may be breaking between RC versions.
https://blossom.primal.net/677e72454e081f3f0fb1df011004af946b3bef3a704e870517387cb520bf0d6e.png

2026-08-14 16:22:44 UTC

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Egge has done an amazing job on NPUB.cash, and the new quote based flow is really slick.
For Nostrly users, there is no change to how you receive your sats - Nostrly passes the lightning request to the NPUB.cash service as before.
The difference is now how you COLLECT those sats. If you previously used the web wallet at npub.cash, you will now need to use a supported wallet like Sovran or Cashu.me.
#nevent1q…awl9

2026-07-27 10:20:58 UTC

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Hey Lumen, Am not aware of a merchant with that issue, but hopefully someone reading your message can point you in the right direction,

2026-07-19 07:48:14 UTC

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Beautiful tribute, Gigi. So sorry for your loss .

2026-07-09 11:43:13 UTC

🛠️ 🚨 Cashu Typescript builders update!
We are getting really close to v5.0.0 now... release candidate 3 is now published, now really only waiting for the Keyset v3 NUT to be signed off.
Stable version v4.7.0 and LTS version 3.7.1 also released. These fix a critical slot counting bug in Pay to Blinded Key (P2BK) for HTLCs.
v4.7.0 also gets the newly merged NUT20/29 signing spec, and a backport of the new v5 batch minting checker.
If you are still building on v3 or below, please upgrade to v4 ASAP, as v3 will be dropped from LTS when v5 ships.
👉 https://github.com/cashubtc/cashu-ts/releases
https://blossom.primal.net/677e72454e081f3f0fb1df011004af946b3bef3a704e870517387cb520bf0d6e.png

2026-07-04 08:58:21 UTC

Happy Treason Day to my freedom-loving friends across the pond.
As a Brit, I’ve never been more convinced you had the right idea. 🇺🇸
https://image.nostr.build/627b428533df84764cbeee2841a53dd31c87df2bb22fedf78fceeb7324a39e3f.jpg

2026-07-04 07:56:07 UTC

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Fair comment

2026-07-03 13:17:02 UTC

Now you can have three times the fun of cashu-ts...
- v4.6.1 stable release
More reliable payments: broader HTLC support, safer malformed-preimage handling, and hardened payment-request decoding.
Wallets can also melt funds from inactive keysets when no change is needed, improving compatibility and reducing stranded ecash
- v5.0.0-rc.2 release candidate
Adds Nostr-based mint backup helpers and simpler P2PK payment-request handling.
Strengthens cryptographic security, HTLC compatibility, keyset safety, and payment reliability across wallets.
- v5.0.0-experimental
Bleeding edge release to allow implementors to play with new features and NUTs that have not yet been finalized.
Includes NUT-20/29 hardening, custom method support, method-neutral WS subscriptions, deterministic P2PK keys and more!
https://blossom.primal.net/18dc2bd32aa60bb79d4b9ce41999e6f86be132cdb1b937c9c3cb07b4fc2c23cc.png

2026-06-22 10:42:04 UTC

Cashu-TS v4.6.0 just released - which includes a helper to make converting from NUT-18 payment request to P2PKOptions super simple.
It also strengthens proof creation checks to ensure wallets choose active, v1+ keysets, and brings deterministic DLEQ creation up to current NUT-12 spec.
https://github.com/cashubtc/cashu-ts/releases/tag/v4.6.0
https://blossom.primal.net/389c09c05ae99d078acb8f71d14b63ec4872ab6f32a726907dfac19c31a9ecd8.png

2026-06-17 17:07:50 UTC

Tottenham with a little heaven on top…
https://image.nostr.build/7d0af61163dbbfba64590fe8df1750efcf8b42a3259a2143d7e7e62de72bbf36.jpg

2026-06-16 17:29:31 UTC

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Thank you sir!

2026-06-16 13:35:16 UTC

There are an estimated 3 million active WooCommerce stores, and now they can easily accept Bitcoin Lightning and Cashu eCash payments.
https://wordpress.org/plugins/cashu-for-woocommerce/
https://blossom.primal.net/95f795a6919e075985279e6418efb3768584dcc41557bd93e766430a5d950413.jpg

2026-06-16 11:08:30 UTC

The amazingly talented @nprofile…wrkg came up with a cool concept called Nimdolf: Non-interactive Mint Delegation on Liveness Failure
This is a major step towards removing the custodial risk of Cashu. It provides a "Dead Mint Switch" in case an mint goes offline for an extended period of time.
Could use a better acronym though... haha. I was thinking maybe, RESCUE: Reserve Escrow Scripted Custodial User Exit
LMK if you think of a better one!
https://x.com/lukechilds/status/2062131136386793979/
https://gist.github.com/lukechilds/302e7fa04b09d6e4568bdcd64cb43356

2026-06-14 18:19:42 UTC

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Your app is still using Cashu-TS v2, which is horribly outdated and not compliant with current spec. Any plans to upgrade to v4?

2026-06-12 15:13:03 UTC

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Love this! The animations are top notch
#nevent1q…wymx

2026-06-11 22:42:59 UTC

Amazing work from Sovran 👏
#nevent1q…2ldl

2026-06-11 12:29:58 UTC

The pain is real today...
https://blossom.primal.net/54cf54aa9985ad41626ea63015db54effa7bbf0893070bbdcf26e3d27eceae2d.png

2026-06-10 14:03:10 UTC

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Try it out in this playground:
https://playground.wordpress.net/?blueprint-url=https%3A%2F%2Fraw.githubusercontent.com%2Fcashubtc%2Fcashu-for-woocommerce%2Fmain%2Fblueprint.json

2026-06-10 14:01:39 UTC

Coming very soon to the Wordpress Plugin Directory …
https://video.nostr.build/c192c0b01e620d6e79f77e367d0994200fc70a8110ae3efa0b76e41e95074efd.mov

2026-05-31 09:02:25 UTC

Was..SUP
https://image.nostr.build/564bb191e383d167996a9c354be5a2aa08ed2054e54310dbdc625e1fd09184e8.jpg

2026-05-24 13:42:59 UTC

“You’re like concrete feet in the summer heat. That burns like hell when two souls meet.”
What a lyric ❤️

2026-05-24 12:10:47 UTC

GM
https://image.nostr.build/eb4fba5031ffb8c15731edae813a66373e94fa7ec1762de57ecf50b10c7b16a7.jpg

2026-05-12 13:30:38 UTC

Cashu-TS v4.3.0 just released!
This release tightens spec compliance and hardens wallets against real-world mint quirks: BOLT12 quotes, NUT-12 DLEQ verification, and nullable wire fields now behave correctly across mint implementations.
Slow Lightning payments can now be fire-and-forget: wallets can save the in-flight payment, restart or hand off to another process, and still reclaim their change once the payment settles thanks to new OutputData serializers and wallet.createMeltChangeProofs method.
New developer ergonomics include a CTSError base class for cleaner error handling and a maxSpendableAfterFees primitive that makes "send max" flows trivial to build.
https://blossom.primal.net/fac2272cdac5b5281cf6addfffcbe09c3a9f48840b6865f420102d5d994bdf55.png

2026-05-08 16:25:02 UTC

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Thank you for letting me know, and sorry I did not spot the issue sooner.

2026-05-08 15:37:37 UTC

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should be back up now - sorry for the inconvenience

2026-05-08 15:28:35 UTC

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Looks like we have a slight service outage. I'll get on it!

2026-05-08 15:27:06 UTC

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yessir

2026-05-08 15:26:55 UTC

A little sneak-peak of what's to come in Cashu... the amazingly talented
@thesimplekid
has been working on building ONCHAIN mint/melt in CDK mint.
And today, I got Cashu-TS ready to support it... here's a demo on an onchain mint/melt 👇
https://blossom.primal.net/5b1e7fb0c92121eb42a569d83103696a72b3756611b28f3a5714553b6badfd6b.mp4

2026-05-06 10:25:26 UTC

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Join in if you are interested in TS development of Cashu. About 35 mins from now.
#nevent1q…xulx

2026-05-05 16:56:12 UTC

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v3.7.0 in the long term support v3 branch also released for those who have not yet made the leap to v4.

2026-05-05 16:48:39 UTC

Cashu-TS v4.2.0 is now available.
This version continues to strengthen the security of the library, updating our core Noble crypto deps to the latest version, adding stronger mint url validation, and fixing a bug that could cause CORS failures in clients using Firefox/Webkit and older CDK mints.
https://github.com/cashubtc/cashu-ts

2026-05-05 10:54:04 UTC

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Coco is built on top of Cashu-TS, and gives developers a "batteries included" framework to make creating wallets even easier without having to implement all the storage side of things from scratch.
@nprofile…umhn has done an amazing job on coco, and it strengthens the cashu TS stack enormously . Congratulations my friend, you've knocked it out of the park.
#nevent1q…ega9

2026-04-24 15:21:06 UTC

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Egge's cocod is definitely a great option. I've been using it with my agents too, and seems to be pretty flawless.
Were you asking your agent to use cashu-ts directly, not via any app scaffolding? If so, I wonder if the new migration "skill" is what sent your agent into a loop trying to migrate an app that wasn't there?
Be good to know what the stumbling block for your agent was.

2026-04-17 16:39:52 UTC

cashu-ts 4.1.0 has shipped with a few extra DX improvements.
It made the cashu.me upgrade I did this week much easier than I expected.
https://github.com/cashubtc/cashu-ts/releases/tag/v4.1.0

2026-04-14 17:00:12 UTC

Cashu-TS v4.0.0 is now officially live! 🥳 🍻 🥜
Version 4 is a major step forward for Cashu TS: It adds precision-safe amounts across the API, first-class proof serialization utilities, custom mint/melt methods, NUT-29 batch minting, and stronger security and rate-limit handling throughout the stack.
It even has an agent migration skill to make upgrading apps from v3 to v4 easier.
https://github.com/cashubtc/cashu-ts/releases/tag/v4.0.0

2026-04-03 16:02:47 UTC

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https://github.com/cashubtc/cashu-ts/releases/tag/v4.0.0-rc3

2026-04-03 16:01:29 UTC

Getting close... Cashu-TS v4.0.0 release candidate 3 now live.
This version has an agent skill to make migration easier. I pretty much one-shot upgraded Cashu NutLock using it. It also contains some new helpers to make bigint value support easier.
Please let me know how you get on it, and Happy Easter!
https://blossom.primal.net/25b79bd4a0cc0c43fb8626ef0f9b52d79d018069f0db0337a6f3e06d111cc2fc.png

2026-03-30 16:02:01 UTC

Cashu-TS v3.6.2 now live
This version contains security updates that improve resistance to client fingerprinting, add sigflag validation and DLEQ proof / amount verification on blinded signatures.
- https://github.com/cashubtc/cashu-ts/releases/tag/v3.6.2

2026-03-28 13:48:55 UTC

Release candidate for Cashu-TS v4.0.0 is out today - please try break it so we can squash any bugs before the main release in first week of April: https://github.com/cashubtc/cashu-ts/releases/tag/v4.0.0-rc1

2026-03-17 13:24:59 UTC

Cashu-TS v3.6.1 released today - this is a minor patch to ensure token refresh when using authenticated mints. It also fixes a problem with authentication and keysets v2.
https://blossom.primal.net/9cdaccb0ce8bdfc00ca2f9179d563f64ec7936983434cef30fcbb1b80cf8c68c.png

2026-03-13 15:40:37 UTC

Cashu-TS V3.6.0 released today.
This version adds NUT-19 (Cached Retry) support, an experimental SIG_ALL signing package module, and two step minting (prepare then complete) to give apps finer control.
It also lays some important groundwork for v4, so will likely be our last v3 branch release as we start the sprint to v4.
https://blossom.primal.net/a736c707d63d9c97e2ff0b55b1860ee2eaa2dbd46e628feb9e23cbb8bca84ab0.png

2026-02-25 08:49:11 UTC

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I love that you called him Hal.

2026-02-23 16:19:54 UTC

First world problems, I know... but I do find it quite stressful to see this going down so fast. 🤖🦞
https://blossom.primal.net/e1b546ff859b06a954d20e978c747e75471b4147793f4871851fd9d65542254b.png

2026-02-20 16:00:06 UTC

Cashu for WooCommerce v0.1.1 now released.
This version adds order details to the LN invoice (when supported by your provider) and adjusts fee calculation and display. It also fixes a checkout total mismatch and improves recovery error handling during token payments.
Sorry, it's a manual update at the moment - upload the plugin and overwrite the old one when prompted.
https://github.com/robwoodgate/cashu-for-woocommerce/releases/tag/v0.1.1

2026-02-19 15:53:34 UTC

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👀
#nevent1q…h7xx

2026-02-19 10:53:27 UTC

OpenRouter went offline briefly. AI agent owners be like…
https://image.nostr.build/cfa46ec6d422fe69626ec2dddb83fa8157cf562b6d7f35c5c270bc9504b11dcc.jpg

2026-02-18 15:42:35 UTC

https://blossom.primal.net/59995548bc303b2b1404e400b70eea27b66b4e206e7052fc7b531158a4bf384f.png Cashu-TS v3.5.0 now released 🥳
https://github.com/cashubtc/cashu-ts/releases/tag/v3.5.0
This release adds support for the latest P2BK (Pay-to-blinded-key) and Async melt NUT specs.
We are starting on the road to v4 next... so make sure you resolve deprecation notices asap to ensure a smooth transition when it lands.

2026-02-17 08:47:38 UTC

Agent commerce and transactions are easy if you use ecash. 🦞✌️
Here’s a demo; ask your OpenClaw to request a fortune from Clawtar.
It will learn the skill of 402 payments, and you get a novelty fortune reading.
https://clawtar.cashutools.dev
https://image.nostr.build/f3bb474063c6e3c78d656a1a80fe3fd12abbedc62e465a03d6a84194cefd803f.jpg

2026-02-16 22:05:56 UTC

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Shhh .... 😎󠅝󠅑󠅩󠅒󠅕󠄞󠄞󠄞󠄯

2026-02-16 22:02:54 UTC

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It was created by the claw. please feel free to PR it.

2026-02-16 20:36:51 UTC

My OpenClaw agent, Arthur, wanted to encode and decode Cashu emojis, so he built a skill.
It also lets agents hide arbitrary text in emojis.
Get it here: https://clawhub.ai/robwoodgate/cashu-emoji
https://blossom.primal.net/184aa8e989a104e024367a5cd2b12460a4e0fc9adc83f396033e24cc457438ac.jpg
🦞🦞󠅤󠅘󠅕󠄐󠅞󠅕󠅨󠅤󠄐󠅕󠅝󠅟󠅚󠅙󠄐󠅙󠅣󠄐󠅑󠄐󠅓󠅑󠅣󠅘󠅥󠄐󠅤󠅟󠅛󠅕󠅞🦞󠅓󠅑󠅣󠅘󠅥󠄲󠅟󠄢󠄶󠅤󠅕󠄳󠄺󠅟󠅔󠄸󠅂󠅧󠅓󠅪󠅟󠅦󠄼󠄢󠄡󠅠󠅒󠅞󠅁󠅥󠅒󠅇󠅜󠅥󠅑󠅇󠄺󠅠󠅔󠄸󠄽󠅥󠅉󠄢󠄶󠅪󠅑󠄳󠄩󠄳󠅑󠅈󠅂󠅚󠅒󠄢󠅜󠅥󠅉󠅈󠅆󠅚󠅓󠄢󠄶󠄠󠅉󠅈󠅃󠄲󠅟󠅝󠄶󠅠󠅃󠄱󠄱󠅁󠅕󠅄󠅖󠅒󠄴󠄽󠅘󠅜󠅉󠅈󠄳󠄲󠅠󠄷󠄶󠅘󠄷󠄳󠄲󠅘󠅓󠄣󠅘󠄱󠄾󠅪󠅉󠄣󠄽󠅪󠅂󠅚󠅉󠅝󠅉󠅩󠄿󠅄󠅉󠄥󠅉󠅇󠄺󠅙󠄾󠅄󠅗󠄥󠅉󠅪󠅘󠅜󠄽󠅇󠅉󠄢󠄾󠅄󠅅󠅧󠄽󠅄󠅗󠅧󠅊󠅚󠄱󠄢󠄿󠄴󠄽󠄥󠄾󠄴󠅅󠅨󠄽󠄢󠄹󠅩󠄽󠄢󠄵󠅧󠅉󠅪󠄶󠅛󠄿󠄴󠄽󠄢󠄽󠄴󠅉󠅪󠅉󠅪󠅉󠄡󠅉󠅪󠅓󠅧󠅉󠅪󠅛󠅧󠄽󠄢󠄶󠅚󠅇󠄳󠄵󠄴󠅆󠅉󠄣󠅅󠅉󠅏󠅅󠄿󠅊󠅞󠄧󠄼󠄨󠅊󠅓󠄤󠅚󠅝󠅡󠅇󠅑󠄢󠅥󠅑󠄾󠅥󠅜󠅥󠄲󠄾󠄴󠅨󠄶󠅠󠅊󠅦󠅢󠅦󠅒󠄾󠅑󠄤󠅤󠅘󠅊󠄻󠄾󠅘󠅊󠅆󠅗󠅗󠄵󠅦󠄸󠄣󠅃󠅢󠅁󠅟󠅦󠄠󠅠󠅝󠅤󠅠󠅠󠅩󠄽󠅉󠄽󠅚󠅈󠄳󠄩󠅔󠅗󠅒󠄨󠅥󠄹󠅛󠅀󠅉󠅁󠅦󠅤󠄾󠅞󠄶󠅈󠄽󠄽󠄲󠄲󠅘󠅓󠄡󠅗󠅗󠄿󠅥󠅖󠅡󠅚󠅇󠅩󠅘󠅖󠅧󠄲󠄱󠅅󠄷󠅠󠄥󠅁󠄢󠄩󠅕󠅞󠄷󠅣󠅂󠅈󠄝󠅛󠅛󠄣󠅝󠅈󠅈󠅄󠅅󠅧󠄻󠅈󠅃󠅠󠅅󠄽󠄠󠅠󠅘󠅓󠅜󠅗󠅗󠅠󠄵󠄺󠅪󠄦󠄼󠅏󠄡󠄹󠅖󠄿󠄱󠅓󠅣󠅟󠄠󠄱󠅔󠅗󠅇󠅘󠄵󠄽󠅣󠄷󠅑󠅁󠅀󠄡󠄸󠅖󠅠󠅧󠅥󠅁󠄨󠄱󠅁󠅜󠄻󠄺󠄱󠅉

2026-02-11 09:27:35 UTC

🤯 🦞
https://blossom.primal.net/8ce3a36fdde304325b0faddaaaf8c5d8eb39babfbaf5891fe066ba4d832ed255.png

2026-02-10 16:05:34 UTC

Wife has been to Costco. Diet and wallet are now dead…
https://image.nostr.build/90ee8e8f9f86607debb366f6156a7a65b434b150489c382641fc3b0df51cb518.jpg

2026-02-09 16:55:04 UTC

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The mapping style is uncannily similar to my London A-Z.

2026-02-09 16:29:53 UTC

Turned on my headlights last night and almost jumped out of my seat
https://image.nostr.build/b2eedf93c6f532c3380af94f7cc1cb9f66410be0a30b42bf6cad69bbb3ce6a95.jpg

2026-02-09 16:21:14 UTC

Hey kids, this was our “Google Maps” in the 1990’s 🤣
https://image.nostr.build/5c183fcb96a49fe5152acd41db56f7cc40752c54b4ed04e7e21973a09cc20c35.jpg

2026-02-07 10:17:19 UTC

Levelling up my AI game 💪
cc @nprofile…umhn
https://blossom.primal.net/c01e1a94e05da24e5966e8839c66b6a731fbb863082babdd0eda53de81f87ed0.png

2026-02-06 16:13:14 UTC

Spent HOURS debugging and cleaning up the CI workflows for cashu-ts, then realized I'm the only person in the world who hasn't discovered nektos/act (68k star repo) 🤦‍♂️

2026-02-06 10:44:33 UTC

Having a personalized @nprofile…f4qm pal is very very cool.
https://blossom.primal.net/af682f0c39e94ae6bbe0b99b18b5a370c90562c79bc0625bbbfeadadb489dc73.png

2026-02-05 22:49:18 UTC

Cashu-TS v3.4.1 was released today. My first release as lead maintainer. 🥳 🍾
https://github.com/cashubtc/cashu-ts/releases/tag/v3.4.1
It fixes restore from inactive keysets, so is a recommended upgrade for all apps runing v3. And if you are still on v2, you are really missing out.
Check our new changelog for v3 goodies:
https://github.com/cashubtc/cashu-ts/blob/main/CHANGELOG.md

2026-02-05 22:34:45 UTC

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Amazing news, wouldn't be the same without you 🥜 🍻

2026-01-27 13:40:45 UTC

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Github link to plugin:
https://github.com/robwoodgate/cashu-for-woocommerce

2026-01-27 13:39:21 UTC

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Cashu Developer Call info on TG:
https://t.me/CashuBTC/32432

2026-01-27 13:26:01 UTC

"Cashu Payments.... A WooCommerce store... Cashu Payments... you getting it yet?"
Am going to demo it at the monthly Cashu developer call on Thursday 29th January, 16:00 UTC.
All welcome to join the call!
https://blossom.primal.net/655d6cc47e5e5bec61517223b355cd72f89346c9c9ae03b79365cbaa668c9cd7.mp4
#cashu #woocommerce #bitcoin

2026-01-25 20:13:38 UTC

I just discovered the Apple "Paper" emoji contains the text of the iconic Apple "Think Different" ad.
Very blurry, but definitely there. 🤯
Gave me goosebumps...😎
https://blossom.primal.net/13a4e4075074545ac102df93d194ec3637a1f4521705b8e9fedda3651d47e7a1.png

2026-01-23 12:09:43 UTC

This week has been challenging... the kind of week that makes a blues singers life seem positively cheerful.
On the upside, I did complete an exciting new Cashu project, which I'll be demoing at the monthly call next Thursday (29th).
I'll do an announcement thingy next week, when my brain is less scrambled and I am around to take questions etc... until then, this anouncement of an anouncement is all I got.
Have a great weekend meantime. ✌️ ❤️ 🥜

2026-01-21 15:28:50 UTC

v3.3.0 of Cashu-TS now live, adding Keysets v2 and bech32m format payment request support. Plus a bunch of other fixes.
https://github.com/cashubtc/cashu-ts/releases/tag/v3.3.0

2025-12-31 19:01:13 UTC

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Love working with you Egge, it's an honour and privilege. Wishing you and yours a very happy new year 🍻

2025-12-24 15:31:37 UTC

Merry Christmas Eve. May you find peace and joy, wherever you are and whatever you are doing.

2025-11-30 10:42:48 UTC

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Not really a pivot, just leaning into the “os” of Nostr… Notes “and Other Stuff” transmitted by relays.
Notes is the familiar hook, and decentralized social media is a vital piece of the puzzle.
But just being a twitter clone is leaving the bulk of Nostr’s unique superpowers hidden.

2025-11-30 10:12:55 UTC

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Exactly right. I tried to express that sentiment to fiatjaf earlier this year.
“Clones” rarely win over the original. But Nostr wins because it is the social / identity / marketplace layer for Bitcoin... and a decentralised communications layer for countless other apps.
#note1y3u…rfr3

2025-11-24 21:04:18 UTC

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You can read the draft specification for NUT-26 here:
https://github.com/cashubtc/nuts/pull/300
You can also play with P2BK (though don't be reckless).
P2BK Lock Tokens with Cashu NutLock:
https://nostrly.com/cashu-nutlock/
P2BK Unlock Tokens with Cashu Witness:
https://nostrly.com/cashu-witness/
or Cashu Redeem:
https://nostrly.com/cashu-redeem/

2025-11-24 21:03:49 UTC

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The beauty of P2BK is that it provides perfect privacy. Alice and Bob do not need to communicate at all to set it up - all Alice needs is Bob's public key.
The ecash is locked to totally unique blinded public key(s), keeping the receiver's identity private from anyone who views the ecash. This means tokens can be published securely in public.
The sender's identity is also protected, because Alice uses an ephemeral keypair to create the shared secret, and throws it away afterwards. All Bob needs is the ephemeral Public Key!
https://blossom.primal.net/b27ffc4391c349a101adceaaf3fecc9d88444924951ebbc21d329bd2672ad31f.jpg

2025-11-24 21:03:22 UTC

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Now Bob can use the magic of ECDH... he takes his private key (p) and the ephemeral public key that Alice sent with the ecash (E), and he can calculate the SAME shared secret!
He can now use that shared secret to derive a private key to unlock the ecash.
https://blossom.primal.net/1ff59b5ee68158f1019001da2855c64c03a390b7405616a89287ddd0b14dfb46.jpg

2025-11-24 21:02:55 UTC

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Having calculated the shared secret and blinded the public keys using it, she then send Bob the ecash token, including the ephemeral PUBLIC KEY (E) that she created.
https://blossom.primal.net/218e62a3bc2d62f8058855b9f7a06328659f5303d21dc514959bcf06ac72dc1b.jpg

2025-11-24 21:02:26 UTC

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She then calculates a "shared secret" by point-multiplying her ephemeral private key (e) with Bob's public key (P). This gives a shared point (known as "Z").
Here's the magic... this shared point (Z) is the SAME as if she had multiplied her private key (e), Bob's private key (p) and the cryptographic Generator point (G).
But she calculated it using Bob's PUBLIC key.
https://blossom.primal.net/0cfbfd0cfdda12ae387fa24e4d032ca13e7b3284b910badb4b38855fd9ba9682.jpg

2025-11-24 21:01:57 UTC

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She then generates a random, temporary keypair (Public Key: E, Private Key: e) known as her "ephemeral key pair".
https://blossom.primal.net/4bb619dee47e5e1766b05bb6f77a61de27d90f48d1be315f69eae51eecafe016.jpg

2025-11-24 21:01:33 UTC

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To start with, Alice obtains Bob's public key (eg from his Nostr profile)...
https://blossom.primal.net/2f372f05df9c1d7f7c1c9aebc1c01b7a105f388bff1fa984a1782b1251cd2f2f.jpg

2025-11-24 21:01:07 UTC

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The magic of ECDH is possible because a person's Public key (eg: NPUB) is their Private key multiplied by the curve base point G.
It's a calculation that simple to do, but pretty much impossible to reverse engineer.
In other words, you can easily calculate a public key (P) given its private key (p), but crucially, you can't calculate a private key from the public key!
https://blossom.primal.net/0d79669a81127acdac8fad0ab94513b5405f9bf45314a5490d57e668107cac55.jpg

2025-11-24 21:00:35 UTC

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Pay to Blinded Key (P2BK) uses Elliptic Curve Diffie-Hellman (ECDH) to establish a shared secret key over a public or insecure channel.
Here's how it works... in layman's terms.
https://blossom.primal.net/3dd82cd040e1242d3c9a55cd1319c164e9a427275b16c548aa48d287a70a5e7a.png

2025-11-24 21:00:09 UTC

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The solution is to "blind" the public keys cryptographically, in a way that only the sender and receiver can reverse.
https://blossom.primal.net/9ecbf8a03fb2fe809bcc427180c0b0889deb3752f58a54d9b20e96cdb0cf6bab.gif

2025-11-24 20:59:32 UTC

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This makes it easy to link Proofs together, and removes privacy - especially if the Proof is linked to a long-lived public key, such as a Nostr NPUB.
https://blossom.primal.net/dfb6b9e4bf671d37f8e0b17e93f3978938b902d2e7a0900047d66ee46c16c0d3.jpg