How does chain convergence connect Internet computers to Bitcoin?

Chain fusion

Chain fusion is a set of protocols that allow smart contracts on Internet computers (ICPs) to directly read, hold, and sign transactions on Bitcoin and other blockchain without having to bridge or encapsulate tokens to transfer funds. Instead of relying on third-party custodians to lock bitcoins and make copies elsewhere, ICP nodes run their own bitcoin adapters and use threshold cryptography to control the real bitcoin address. According to reports, bridging has been the single largest source of loss in cryptocurrency history.

How does chain convergence actually work?

Chain fusion is built on two core components: a network directly connected to the blockchain itself, and a signature technology called chain-key cryptography.

First, understand some basic terms. On Internet computers, containers refer to smart contracts, Mini programs that run on the network and hold funds or logic. A node is a computer in a network; multiple nodes work together and authenticate each other.

For Bitcoin, ICP adopts a "direct integration" approach. A set of ICP nodes run special software called Bitcoin Adapters, which connects directly to Bitcoin's own network and downloads its data in the same way as any Bitcoin software. Together, these nodes act as real Bitcoin nodes, so the container can check its own balance at any Bitcoin address and send Bitcoin transactions without any obstacles in the middle-no external company, intermediary, or bridge is needed.

The second part is the cleverness: How can a container, a software without a physical body,"hold" real Bitcoin? Each container can generate a digital key on which the Bitcoin address relies and then request the network to use that key to sign the transaction. But no computer independently holds a complete private key. Instead, a group of nodes work together to generate a valid signature as a team, similar to a bank vault that requires multiple managers to turn the key at the same time to open it. No manager can open it alone, and the same protection mechanism applies here: no single node, and no hacker who breaches a single node, can transfer funds.

For blockchains that have not yet established such direct connections, ICP adopts a second, simpler approach.

How does ICP connect Ethereum and Solana?

For these chains, the container sends a normal web request (the same type of request sent when a browser loads a page) to an external company running an Ethereum or Solana server. To avoid trusting any single company, ICP sends the same request to at least three different companies simultaneously and compares their responses. If all answers are consistent, the result is accepted. If there is no agreement, the container must resolve the differences on its own, rather than blindly trusting a source.

This is a practical trade-off worth explaining. For a direct connection to Bitcoin, you only need to trust that most of the ICP nodes involved are honest. And with Ethereum and Solana's methods, you also need to trust the external server company not to lie, although mutual verification of the three sources makes counterfeiting more difficult. Bitcoin received stronger guarantees, while Ethereum and Solana received weaker guarantees, but enhanced security by requiring agreement from multiple external sources.

What is ckBTC? Why not need a bridge?

The clearest daily example of chain fusion is a token called ckBTC, an abbreviation for "Chain Key Bitcoin." You can think of it as an alternative to real Bitcoin, which exists on Internet computers rather than the Bitcoin network, and is therefore faster and cheaper. It is anchored in a 1:1 ratio to real Bitcoin, but unlike similar products elsewhere, there is no centralized company handling the exchange of BTC to ckBTC in the middle.

Here is how it differs from the typical "encapsulated Bitcoin" you may see on other blockchains:

encapsulated Bitcoin tokens are usually caused by a company or a small group storing the real BTC in a vault and then issuing IOUs elsewhere. If the company is hacked or behaves dishonestly, even if the IOUs claim to be "backed by assets," it could become worthless.

ckBTC completely bypasses this setting. Internet computers are directly connected to the Bitcoin network itself, so there are no companies or vaults for hackers to attack. Exchange rates never change: one ckBTC is always exactly equal to one real Bitcoin, and you can exchange the two for each other at any time.

Speed and cost vary significantly. ckBTC payments settle in seconds and cost as little as a fraction of a penny, while ordinary Bitcoin payments typically take about an hour to be fully confirmed and are accompanied by actual transaction fees. The only thing you have to wait is your first conversion: Converting real BTC to ckBTC still means sending a real Bitcoin transaction, so the first step takes about an hour and pays for normal network fees for Bitcoin. After that, every ckBTC transfer was almost instantaneous.

Where is this technology currently used?

Chain-fused Bitcoin connectivity is more than just a technical demonstration. It is already running in actual products and covers several categories:

Use Bitcoin to borrow, pledge, and earn income

Some apps now allow people to directly leverage their Bitcoin without first sending it to a centralized exchange. For example, users can mortgage a loan with Bitcoin, or pledge Bitcoin to earn a return, with the rate of return depending on the length of time they agree to lock in.

Transferring Bitcoin between different blockchain ecosystems

DFINITY, the organization behind Internet Computers, has worked with other networks to extend ckBTC to their platforms, using chain convergence so that these transfers still avoid the use of bridges.

Directly traded on exchanges

ckBTC has been listed as a separate asset on a centralized exchange, indicating that it is considered a real, redeemable Bitcoin rather than a counterfeit token.

What will be the status of ICP in mid-2026?

As of August 10, 2026, according to data, the ICP trading price was US$2.19, up 2% in the past 24 hours and 7% in the past 7 days. The rebound comes after a difficult period: ICP hit a record low of about $2.00 on August 1, 2026, and then rebounded. The current market value is approximately US$1.21 billion, and the circulating supply is approximately 560 million ICP. There is no fixed maximum supply.

Internet usage tells more than price. In July 2026, ICP processed 3.16 billion transactions, making it the world's second most active blockchain after Solana. At the same time, its market value of approximately $1.15 billion is approximately 91 times the total lock-in value on DeFiLlama of approximately $12.6 million, a gap that analysts point to suggests high transaction throughput has not yet translated into corresponding DeFi capital.

In terms of token economics, the networked nervous system approved an upgrade called "Mission 70" in January 2026, with the goal of reducing the annual ICP inflation rate from approximately 9.7% to a target range of 2.9% to 5.4% by the end of 2026. It achieves this goal by limiting pledge rewards and accelerating the destruction of cycles (the units used to pay for network computing).

What are the risks of chain convergence and ckBTC?

Chain fusion eliminates the risks posed by bridging, but this does not mean there are no risks at all. The system still relies on the fact that most computers in a given group are honest, and the "multiple managers share a key" signature technique, while deeply researched by cryptographers, is complex enough that external review is crucial. Independent security researchers, including a team called Bitcoin Layers, have released a review of the way ckBTC is built because the technology is new enough and requires a second opinion, rather than just believing what the project says.

FAQs

Does ckBTC require a bridge to work?

No need. ckBTC is forged and redeemed through container smart contracts, which directly hold real bitcoins, signed using a chain key rather than a bridge contract or custodian.

Can chain fusion connect ICP to chains other than Bitcoin?

Yes. Bitcoin uses direct node-level integration, while Ethereum, Solana and other chains connect to RPC providers via HTTPS outbound calls, resulting in cross-verification by multiple independent providers before being accepted by the container.

Is ckBTC the same value as Bitcoin?

Yes. One ckBTC can always be exchanged for one BTC. The token accurately tracks the value of Bitcoin; what changes is the speed and cost, because ckBTC settles in one to two seconds, and the fee is about 10 Satoshi.

Conclusion

Chain fusion allows ICP containers to hold Bitcoin addresses, read UTXO sets, and sign valid Bitcoin transactions directly, using threshold cryptography rather than bridges or custodians. ckBTC converts this capability into a usable, 1:1 redeemable token with sub-second settlement and near-zero fees. The connection between Ethereum and Solana is achieved through another RPC-based path, with its own trust model. Together, these components enable Bitcoin to be used in DeFi, lending and pledge applications, while the underlying currency maintains verifiable asset support on the Bitcoin network.