DLCs (Discreet Log Contracts): Bitcoin Smart Contracts

Jun 26, 2024


Bitcoin, the world's first cryptocurrency, has always been about more than just digital money. Its underlying technology holds the potential for complex financial agreements and smart contracts. Enter Discreet Log Contracts (DLCs) - a groundbreaking development that's pushing the boundaries of what's possible on the Bitcoin network.

TLDR: What are DLCs and How Are They Used?

Discreet Log Contracts are a type of Bitcoin smart contract that allows two parties to enter into an agreement based on future real-world outcomes. They solve key challenges of scalability, privacy, and oracle trust that have hindered widespread adoption of smart contracts on Bitcoin.

As an example of DLCs in action, consider Liquidium, a non-custodial peer-to-peer lending platform on Bitcoin. Liquidium uses DLCs to create secure, efficient loans where users can borrow Bitcoin against their digital assets like Ordinals or Runes. Each loan is secured by a DLC that acts as an escrow, automatically releasing the collateral based on predefined conditions without requiring trust between parties or in a centralized authority.

The Genesis of Discreet Log Contracts

Introduced by Thaddeus Dryja from the MIT Digital Currency Initiative, DLCs were designed to address the limitations of traditional smart contracts on Bitcoin. The goal was to create a system that could handle complex agreements while maintaining Bitcoin's core principles of security, privacy, and decentralization.

Now, let's dive deeper into the world of DLCs and explore how they're transforming Bitcoin's capabilities.

How DLCs Work:

At their core, DLCs involve three key players:

1. Alice and Bob: The two parties entering into the contract.

2. Olivia: An oracle that provides external data to resolve the contract.

The magic of DLCs lies in their clever use of cryptography. They employ a modified version of Schnorr signatures, a cryptographic technique already familiar to the Bitcoin community. Here's a simplified breakdown of the process:

1. Contract Creation: Alice and Bob create multiple potential outcome transactions, each corresponding to different possible results of their agreement.

2. Oracle Commitment: Olivia, the oracle, commits to a public key and a one-time signing key in advance.

3. Execution: When the contract's conditions are met, Olivia signs the outcome. This signature reveals the information needed to execute the appropriate transaction.

4. Settlement: The correct transaction is broadcast to the Bitcoin network, settling the contract according to the agreed-upon terms.

Key Advantages of DLCs:

1. Privacy: DLCs blend in with regular Bitcoin transactions, enhancing user privacy.

2. Scalability: By keeping most data off-chain, DLCs reduce the burden on the Bitcoin network.

3. Minimized Oracle Trust: The system is designed so that oracles can't manipulate outcomes without detection.

4. Flexibility: DLCs can handle a wide variety of agreements based on real-world events or data.

Real-World Application: Liquidium's Lending Platform

To understand how DLCs work in practice, let's look closer at Liquidium's implementation:

1. Loan Creation: When a borrower and lender agree on terms, they create a DLC that acts as an escrow for the collateral.

2. Time-Based Contracts: The DLC's expiration is set to match the loan duration, eliminating the need for complex price-based liquidations.

3. Automatic Execution: If the borrower repays on time, the DLC releases the collateral back to them. If not, it allows the lender to claim the collateral.

4. Decentralized Security: Even if the oracle misbehaves, the borrower and lender together can still release the collateral, ensuring a truly permissionless system.

This implementation showcases how DLCs can create trustless, efficient financial products on Bitcoin without relying on centralized authorities.

Future Potential and Challenges

While DLCs offer exciting possibilities, there's still work to be done. Researchers are exploring optimizations to make DLCs even more efficient and user-friendly. Some areas of focus include:

1. Reducing computation requirements for contracts with many possible outcomes.

2. Integrating DLCs with the Lightning Network for even faster, cheaper transactions.

3. Developing systems for parties to easily find and match with potential counterparties.


Discreet Log Contracts represent a significant leap forward in Bitcoin's evolution. By enabling complex, trustless agreements while maintaining Bitcoin's core principles, DLCs are opening up new possibilities for decentralized finance, prediction markets, and more.

As projects like Liquidium demonstrate, DLCs are not just theoretical – they're already being put to use in innovative ways. As development continues and more people recognize the potential of this technology, we can expect to see an explosion of new applications built on Bitcoin using DLCs.

The future of Bitcoin smart contracts is here, and it's discreet, scalable, and full of potential. Whether you're a developer, investor, or simply a Bitcoin enthusiast, keeping an eye on DLCs could give you a glimpse into the future of decentralized agreements and financial products.

Liquidium is the leading peer-to-peer Bitcoin lending protocol, using Ordinal Inscriptions as collateral enabled by PSBTs and DLCs on Layer-1 Bitcoin.