Welcome to The Protocol, CoinDesk's weekly wrap of the most important stories in cryptocurrency tech development. I’m Margaux Nijkerk, a reporter at CoinDesk.

In this issue:

• Stripe-Backed Blockchain Tempo Starts Testnet; Kalshi, Mastercard, UBS Added as Partners
• ZKsync Lite to Shut Down in 2026 as Matter Labs Moves On
• Blockstream Connects Lightning and Liquid for Faster, Private Bitcoin Payments
• Axelar Unveils AgentFlux to Bring AI Agents Onchain, Without Cloud Risks

Network News

STRIPE’S TEMPO TESTNET GOES LIVE: Tempo, a payments-focused blockchain backed by Stripe and crypto investment firm Paradigm, launched its public testnet, a key step in its effort in making stablecoin payments for mainstream use. Tempo also unveiled a roster of additions to the network’s partner group, including buy-now-pay-later firm Klarna, predictions market Kalshi, payments giant Mastercard and Swiss global bank UBS. They join a group of earlier design partners such as Deutsche Bank, Visa, Shopify, OpenAI and Nubank. Initially introduced in September, Tempo is designed to handle high-volume financial transactions with low fees, instant finality and native support for stablecoins. Now the testnet is live, developers and corporate partners can begin experimenting with real-world payments onchain. The move fits into the latest trend of building blockchains for stablecoin payments as adoption of digital dollars soars globally. Currently a $300 billion asset class, stablecoins are projected to become an integral part of cross-border payment rails with business-to-business (B2B), peer-to-peer (P2P) and card payments driving growth, a recent report by Keyrock and Bitso said. Tempo aims to solve common pain points in blockchain-based finance like network congestion and volatile transaction fees. The network charges around one-tenth of a cent per transaction, payable in U.S. dollar-denominated stablecoins and eliminating the need for a volatile gas token. — Krisztian Sandor Read more.

ZKSYNC LITE TO SUNSET IN 2026: Matter Labs plans to deprecate ZKsync Lite, the first iteration of its Ethereum layer-2 network, the team said in a post on X over the weekend. The company framed the move, happening in early 2026, as a planned sunset for an early proof-of-concept that helped validate their zero-knowledge rollup design choices before newer systems went live. ZKsync Lite, which debuted in 2020, was built for basic token transfers, and took a back seat after developers released ZKsync Era in March 2023, a more advanced zkEVM rollup, which now anchors the project’s broader ZK Stack roadmap. The Lite network will continue operating for now, with funds remaining safe and withdrawals to Ethereum mainnet still available, the team said. A detailed migration plan and timetable for the shutdown will be published next year. — Margaux Nijkerk Read more.

BLOCKSTREAM APP INTRODUCES LIGHTNING ATOMIC SWAPS: Blockstream has rolled out an update to its mobile app that allows users to swap between Bitcoin’s Lightning and Liquid networks, aiming to lower the entry barrier for private, fast bitcoin payments. A fresh version of the Blockstream Green app introduces support for trustless atomic swaps between Lightning and Liquid. The change lets users pay Lightning invoices directly from their Liquid bitcoin (LBTC) balances, avoiding the need to manage Lightning channels or maintain inbound liquidity, a process that can be technically challenging for many. Lightning is designed for instant, low-fee bitcoin payments. Liquid, by contrast, is a sidechain that offers confidential transactions and easier management of unspent bitcoin outputs (UTXOs). By linking the two networks through atomic swaps, Blockstream is attempting to give users the benefits of both without requiring deep technical involvement. The swap process happens self-custodially and relies on cryptographic hash locks, ensuring that both sides of the transaction are completed or neither is. If something fails, funds return automatically to the original wallet. — Helene Braun Read more.

AXELAR UNVEILS NEW PRIVACY AI FRAMEWORK: Axelar unveiled AgentFlux, an open-source framework designed to run AI agents locally while keeping private keys, trading strategies and client data off the cloud — a pitch aimed squarely at institutions exploring onchain finance and wary of privacy risks. Developed by Interop Labs, the team behind the Axelar network, AgentFlux lets financial firms deploy “agentic” automation without sending sensitive information to external infrastructure, the company announced. The framework tackles one of the biggest frictions in AI-driven crypto operations: tool-calling. Most agents today rely on cloud-based models to decide which blockchain tools to invoke and how to structure transactions, which can unintentionally expose the very information institutions seek to protect. AgentFlux splits those tasks into two smaller, specialized models — one for picking the right tool, and another for generating the arguments to execute. According to the team behind Axelar, this setup improves tool-calling accuracy by 46% on benchmark tests, bringing local models closer to the performance of larger cloud systems. – Margaux Nijkerk Read more.

In Other News

• Superstate, a blockchain-focused financial technology firm, rolled out a new platform that allows U.S. Securities and Exchange Commission (SEC)-registered public companies to issue shares directly onchain to investors on Ethereum. Called the Direct Issuance Program, Superstate's new initiative allows companies to raise capital by selling newly issued, tokenized equity in exchange for stablecoins. Investors receive the tokenized shares immediately, and the company’s shareholder records are updated in real time via Superstate’s SEC-registered transfer agent infrastructure. First issuers are expected to go live next year, the firm said. The move comes as tokenization is gaining traction with financial institutions and other businesses exploring blockchain rails for efficiency gains. In an interview last week, SEC Chairman Paul Atkins said tokenization could "reshape the financial system" over the next few years, underscoring how regulators are opening the door to blockchain as part of the next generation of market infrastructure. — Krisztian Sandor Read more.
• BitMine Immersion Technologies (BMNR), the Ethereum-focused digital asset treasury firm, acquired 138,452 ether last week, accelerating an accumulation strategy that lifted its total holdings to 3.86 million tokens, the company reported. At current ETH prices, last week’s acquisition is worth roughly $435 million. That's a 156% increase from four weeks ago when it added about 54,000 ETH, the firm pointed out, and it's also higher than the previous two weeks' haul of 97,000 and 70,000 tokens. The firm also increased its cash holdings to $1 billion, up from the previous week's $882 million. Including a small bitcoin stash and a stake in Eightco Holdings (ORBS), the company's total crypto and cash assets are worth $13.2 billion. The latest purchase increases BitMine’s share of the second largest cryptocurrency's circulating supply to over 3.2%, reinforcing its position as the largest known ETH treasury. — Krisztian Sandor Read more.

Regulatory and Policy

• A Republican U.S. senator at the center of talks over the crypto market structure bill that's the industry's top policy priority, Senator Cynthia Lummis, said the White House resisted ethics language she hashed out with Democrats. That's left the Wyoming lawmaker as a go-between trying to satisfy Democratic colleagues in the bipartisan talks while convincing the White House to come along, she said at the Blockchain Association's policy summit in Washington. Still, she thinks the negotiators should reveal their working draft by the end of the week and formally mark it up next week. Lummis said that she and Democratic Senator Ruben Gallego had come up with some language on ethics. While she wasn't explicit about details, one of the sticking points for Democrats has been their demand that top government officials shouldn't be allowed to profit from the industry over which they hold policy authority — pointedly aimed mostly at President Donald Trump and his family's crypto businesses. — Jesse Hamilton Read more.
• The U.S.’ second-largest teacher’s union urged the Senate to reconsider a crypto bill it says puts 1.8 million members’ pensions at risk, while doing very little to fight fraud and corruption in the digital assets sector. In a letter dated Dec. 8 obtained by CNBC, Randi Weingarten, president of the American Federation of Teachers (AFT), addressed the U.S. Senate Banking Committee over the Responsible Financial Innovation Act, saying, “it poses profound risks to the pensions of working families and the overall stability of the economy”. The proposal, which builds on a measure the House passed earlier this year, is co-sponsored by crypto ally Senator Cynthia Lummis and Senator Bernie Moreno , along with Senate Banking Committee Chair Tim Scott. While the bill lays out a framework for overseeing digital assets, it also raises fresh questions about how tokenized securities, instruments that aren’t strictly cryptocurrencies, would be treated by regulators. “The legislation on crypto we have seen weighed by the committee over the last few months gives us deep concern,” Weingarten wrote. “It is as irresponsible as it is reckless. We believe that if enacted, this bill has the potential to lay the groundwork for the next financial crisis … Beyond the threat to the retirement security of working families, the legislation being considered by the committee does little to curb the illegal activity, fraud and corruption that continues to be prevalent in anonymous crypto markets,” he wrote. — Olivier Acuna Read more.

Calendar

• Dec. 11-13: Solana Breakpoint, Abu Dhabi
• Feb. 10-12, 2026: Consensus, Hong Kong
• Feb. 17-21, 2026: EthDenver, Denver
• Mar. 30-Apr. 2, 2026: EthCC, Cannes
• Apr.15-16, 2026: Paris Blockchain Week, Paris
• May 5-7, 2026: Consensus, Miami