تراکنش‌های قفل زمانی مونرو: نحوه زمان‌بندی انتقال XMR

What Are Time-Locked Transactions in Monero?

Monero includes a built-in mechanism that allows senders to create transactions whose outputs cannot be spent by the recipient until a specified future time or block height. This feature, known as unlock_time, enables time-locked transactions directly at the protocol level without requiring smart contracts or third-party services. While not widely used in everyday transactions, time-locked transactions serve important roles in escrow arrangements, scheduled payments, and inheritance planning.

Unlike some other cryptocurrencies that require complex scripting for time-based conditions, Monero's approach is elegant and straightforward. The unlock_time parameter is embedded directly in the transaction data, and the network enforces the lock automatically. Until the specified condition is met, the recipient can see the incoming funds in their wallet but cannot include them as inputs in any new transaction.

Understanding the Default 10-Block Lock

Before exploring custom time locks, it is important to understand that every Monero transaction already includes a default lock. All newly received outputs are locked for 10 blocks (approximately 20 minutes) before they can be spent. This default lock serves a critical purpose in Monero's privacy model.

The 10-block lock ensures that newly created outputs have time to propagate across the network and become available as potential decoys in other users' ring signatures. If outputs could be spent immediately, a freshly created output appearing as a ring member would be statistically more likely to be the real spend, weakening the privacy guarantees for all users. This default lock is non-negotiable and applies to every transaction regardless of any additional custom lock time.

How Lock Time Is Calculated

Monero's unlock_time field accepts two types of values:

• Block height: Any value less than 500,000,000 is interpreted as a block height. The output becomes spendable when the blockchain reaches that height. Since Monero produces a block approximately every 2 minutes, you can calculate the target block by adding the desired number of minutes divided by two to the current block height.
• Unix timestamp: Any value of 500,000,000 or greater is interpreted as a Unix timestamp (seconds since January 1, 1970). The output becomes spendable when the network time passes that timestamp.

For most practical purposes, using block heights is more predictable than timestamps, since block times are relatively consistent while timestamp-based locks depend on the median of recent block timestamps as determined by miners.

Use Cases for Time-Locked Transactions

Escrow and Dispute Resolution

One of the most practical applications of time-locked transactions is in escrow arrangements. Consider a scenario where a buyer purchases goods from a seller using Monero. The buyer can send XMR with a time lock that delays availability for, say, 72 hours (approximately 2,160 blocks). If the goods arrive satisfactorily within that window, both parties can proceed normally. If there is a dispute, the time lock provides a window for resolution before the funds become fully spendable.

While this is not a full escrow system with refund capability (Monero time locks are one-directional and cannot be reversed), it does provide a cooling-off period that adds a layer of protection to peer-to-peer transactions.

Scheduled Payments

Freelancers, businesses, and individuals who need to schedule payments can use time-locked transactions to send XMR that becomes available on a specific date. For example, a company could send a contractor's monthly payment at the beginning of the month with a lock that expires on the payment date. The transaction is already confirmed on the blockchain, providing certainty to the recipient that the funds exist and will become available.

This approach has a significant advantage over traditional scheduled payments: the funds are cryptographically committed. The sender cannot cancel or redirect the payment once it is broadcast. The recipient has mathematical proof that the XMR will be theirs on the specified date.

Inheritance and Estate Planning

Time-locked transactions can play a role in cryptocurrency inheritance planning. A holder could create transactions locked far into the future, providing wallet keys and lock details to heirs. Combined with Monero's view keys (which allow monitoring of incoming transactions without spending capability), this creates a verifiable inheritance mechanism.

For example, a parent could send XMR to an address controlled by their child, locked until the child's 18th birthday. The child (or their guardian) could use the view key to confirm the funds exist and track the countdown, but the XMR would remain unspendable until the lock expires.

Personal Savings Discipline

Some users employ time-locked transactions as a form of self-imposed savings discipline. By sending XMR to themselves with a lock period of several months or years, they create a situation where the funds cannot be impulsively spent. This is the cryptocurrency equivalent of a time-deposit or certificate of deposit, enforced by mathematics rather than a bank's terms and conditions.

Creating Time-Locked Transactions in the CLI Wallet

The Monero CLI wallet provides direct support for creating time-locked transactions through the locked_transfer command. Here is a step-by-step guide:

Step 1: Open Your CLI Wallet

Launch the Monero CLI wallet connected to a synchronized daemon. Ensure your wallet is fully synced and has sufficient balance for the transaction plus the network fee.

Step 2: Determine the Lock Parameter

Decide whether to use a block height or a Unix timestamp. To lock for a specific number of blocks from now, first check the current block height using the status command in monerod, then add the desired number of blocks.

For a 30-day lock, calculate approximately 30 days multiplied by 24 hours multiplied by 30 blocks per hour, which gives roughly 21,600 blocks. Add this to the current block height to get your target.

Step 3: Execute the Locked Transfer

Use the following command format in the CLI wallet:

locked_transfer [address] [amount] [lock_block_height]

The wallet will display the transaction details including the fee and ask for confirmation. Review the details carefully, paying particular attention to the lock parameter, before confirming.

Step 4: Verify the Transaction

After broadcasting, you can verify the transaction in a block explorer (such as those that show raw transaction data). The unlock_time field in the transaction's extra data will reflect your specified lock parameter.

Security Considerations and Limitations

Irreversibility

The most important consideration with time-locked transactions is their absolute irreversibility. Once broadcast and confirmed, the lock cannot be shortened, extended, or cancelled. There is no mechanism to recover the funds before the lock expires. This makes careful planning essential. Double-check the lock parameter before confirming any time-locked transaction.

Privacy Implications

Time-locked transactions have subtle privacy implications. When an output with a non-standard unlock_time is included as a decoy in another user's ring signature, the lock time could theoretically help narrow down which ring member is the real spend. The Monero protocol accounts for this in its decoy selection algorithm, but extremely unusual lock times (such as locks extending years into the future) could reduce the effective anonymity set.

For this reason, the Monero community generally recommends using time locks conservatively and understanding that very long or very unusual lock periods may slightly impact the privacy properties of the locked output when it eventually becomes spendable.

Interaction with Ring Signatures

A locked output cannot be selected as a decoy in ring signatures until it becomes spendable. This is important because it means locked outputs temporarily reduce the total pool of available decoys. While this effect is negligible given the millions of outputs on the Monero blockchain, it is a theoretical consideration in the protocol's privacy analysis.

GUI Wallet Limitations

As of 2026, the official Monero GUI wallet does not expose the locked_transfer functionality through its graphical interface. Users who need time-locked transactions must use the CLI wallet or a compatible third-party tool. This is partly by design, as the irreversible nature of time locks makes them unsuitable for casual use without careful understanding.

Time Locks vs Multisig for Escrow

While time-locked transactions can serve basic escrow functions, Monero's multisignature (multisig) capabilities are generally more suitable for complex escrow arrangements. Multisig allows multiple parties to share control over funds, with a configurable threshold required to authorize spending. A 2-of-3 multisig arrangement involving buyer, seller, and arbitrator provides genuine dispute resolution capability that time locks alone cannot offer.

The ideal escrow setup often combines both approaches: multisig for shared control and dispute resolution, with time locks as a fallback mechanism to ensure funds are not permanently frozen if one party becomes unresponsive.

Practical Tips for Time-Locked Transactions

• Start small: Before locking significant amounts, practice with small test transactions to ensure you understand the mechanics.
• Use block heights over timestamps: Block heights provide more predictable lock durations since Monero's difficulty adjustment keeps block times relatively stable.
• Document your locks: Keep records of lock parameters, transaction IDs, and expected unlock dates. This is especially important for long-duration locks.
• Consider network upgrades: Monero's hard fork schedule means the protocol evolves. While time locks are a fundamental feature unlikely to change, extremely long locks spanning years should account for potential protocol evolution.
• Inform recipients: If sending locked funds to another person, communicate the lock parameters clearly so they understand when the funds will become available.

Conclusion

Monero's time-locked transaction feature provides a protocol-level mechanism for scheduling when funds become spendable. Whether you need basic escrow functionality, want to create scheduled payments, or are planning for cryptocurrency inheritance, the unlock_time parameter offers a straightforward and mathematically enforced solution. Combined with Monero's comprehensive privacy features, time-locked transactions ensure that even scheduled or delayed transfers maintain full confidentiality of sender, recipient, and amount.

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