TL;DR: So much development is happening in the cryptocurrency ecosystem. It can be difficult to keep up. Crypto Dev Digest (CDD) is a CoinSpice attempt to document all the coolness abounding. This week, it’s a lively digest of double-spend proofs, how CashFusion is coming along nicely, a snazzy conceptual Apple Watch mock-up, and much, much more.

Double-Spend Proofs Just Got Real

Developer Thomas Zander explained, “In Bitcoin Cash the miners and nodes use a ‘first seen’ principle of receiving transactions, which means that accepting unconfirmed transactions (aka instant transactions) is generally speaking safe as any double-spend will be rejected by the entire network.”

However, when a business is attacked “there still are cases where the double-spend can be the one mined. And here is the important part, vendors never get notified of that person in their store trying to double spend. The problem then is that an attacker may try to double-spend a merchant with no detection if he fails, until he succeeds…,” Zander stressed.

He and his team have arrived at what they’re calling double-spend-proofs. “A relatively small (constant size) message with actual proof that the spender signed two different transactions spending the money you were hoping to receive,” Zander continued. “An important part of this work was to make sure the original double-spending transaction can not be reconstructed. So we don’t make it easier for the double spend to propagate.” The comment section alone is worth the read.

Create Bitcoin Cash Smart Contracts with Spedn

Developer Gabriel Cardona provoked a lot of thought-juices flowing with his simple instruction post. Another great comment section read.

Streaming a Mencenas Recurring Payment on BCH

https://t.co/zdMgM64xpJ Setting up a "Mecenas" Recurring Payment on Bitcoin Cash with BCH Developer Karol Trzeszczkowski@vinarmani — Käptn Kook (@KaeptnKook) July 23, 2019

Crescent Cash Rolled Out to the Play Store

Crescent Cash v1.6.1 is now being rolled out to the Play Store! Direct apk and Desktop versions already available on https://t.co/bcoUV9GDNv! pic.twitter.com/uLVl6ggE8s — Crescent Cash (@crescentcash) July 23, 2019

BTC Silently Disabled Bloom Filters

Bitcoin core silently disabled bloom filters in their next milestone release, and they have no plan whatsoever to tell you. Why should you care about bloom filters? Bloom filters are used to allow SPV clients to requests specific transaction and merkle blocks to full nodes. — checksum0 (@checksum0) July 24, 2019

Single-Transaction BCH-for-SLP Trades

I can't stop thinking about single-transaction BCH-for-SLP trades. You provide the SLP input, I provide the BCH input. SLP output goes to me, BCH output goes to you. All in one transaction. Instant transfer, non-custodial, no risk of double-spend (double-spend = full refund) — Ⓥin Ⓐrmani (@vinarmani) July 25, 2019

Badger Supports CashAccounts

When Mainnet? Is No One Using This in Production?

c-lightning: > This implementation is still very much a work in progress. It can be used for testing, but it should not be used for real funds. We do our best to identify and fix problems, and implement missing features. When mainnet? Is no one using this in prod? @FelixWeis? — Andreas Brekken (@abrkn) July 29, 2019

CashFusion Can Offer High Levels of Privacy with Unlinkable Coins

Bitcoin Cash, SLP Tokens on an Apple Watch

Looks so cool. Fingers crossed!

Bitcoin Cash and SLP Tokens available directly from your #applewatch (mainnet & testnet) 😜

Subscribe to the open alpha right now here https://t.co/FvqRxDBoaJ https://t.co/casdS9XhfB — Jean-Baptiste Dominguez @ Tokyo (@jbdtky) July 29, 2019

DISCLOSURE: The author holds cryptocurrency as part of his financial portfolio, including BCH.

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