Comparison: Dynamic vs. Locked Notarization

The IOTA Notarization offers two distinct methods for creating on-chain records: Dynamic and Locked. While both leverage the power of the IOTA ledger to guarantee data integrity, they are designed for fundamentally different purposes. Choosing the right method is crucial for the success of your application.

This guide provides a detailed comparison, analogies, and clear criteria to help you decide which method best suits your needs.

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The Core Analogy: A Living Document vs. A Stone Tablet

To understand the difference intuitively, consider this analogy:

• Locked Notarization is a Stone Tablet. You carve a message into it once. The message is permanent, unchangeable, and serves as a definitive record of a fact at a single point in time. It cannot be altered or passed to someone else to alter. Its purpose is to exist as an immutable artifact.

• Dynamic Notarization is a Living Document or a Public Registry. It has a permanent, well-known location (its ObjectId), but the content inside can be updated. Think of a vehicle's registration status. The car (the object) remains the same, but its status can change from "registered" to "expired" to "sold". Observers only care about the current status, not the history of every previous status.

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Detailed Feature Comparison

Feature	Locked Notarization	Dynamic Notarization
Core Principle	Immutability. Creates a permanent, unchangeable record of a past state.	Availability. Provides a stable reference to the most current, up-to-date state.
State Changes	Not Allowed. The state is written once and is permanently locked.	Allowed. The owner can update the state, overwriting the previous version.
Ownership	Permanent & Non-Transferable. The original creator is the sole and final owner.	Transferable. Ownership can be passed to another address or entity.
Primary Goal	To prove that specific data existed in a fixed state at a specific time.	To provide a reliable and always-current version of evolving data.
Version Tracking	Not applicable, as there is only one version.	Essential. The state_version_count increments with each update.
Timelocks	Mandatory delete_lock to ensure data remains on-chain for a required period.	Optional transfer_lock to temporarily prevent change of ownership.
Lifecycle	Create → Hold → Destroy	Create → Update → (Optional) Transfer → Destroy

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When to Use Which Method?

Your choice depends entirely on the nature of the data you are notarizing: is it a static fact or an evolving state?

Use Locked Notarization if:

You need to create a permanent, historical record that must be proven to be unaltered. Your primary concern is finality and legal-admissibility.

• You need to prove authorship or existence.
  • Example: Timestamping a patent application, a manuscript, or a piece of software to prove it existed before a certain date.
• The data represents a final, unchangeable event.
  • Example: Issuing a birth certificate, a university diploma, or a legal verdict. These are facts that, once established, do not change.
• You are creating a legally binding snapshot.
  • Example: Notarizing a signed contract, a financial statement at the end of a fiscal year, or an audit report.
• The record must remain on-chain for a specific compliance period.
  • Example: A Digital Product Passport for a non-serviceable part, where the manufacturing data must be available for 10 years.

Use Dynamic Notarization if:

You need to provide a single, reliable source of truth for data that changes over time. Your primary concern is ensuring everyone has access to the latest information.

• The data tracks the status of an asset or process.
  • Example: A Digital Product Passport for a car, where the state is updated to reflect maintenance, ownership changes, and repairs over its lifetime.
• You are managing a public list or registry.
  • Example: An allowlist for a service, a list of authorized members in a consortium, or an identity revocation list.
• The data is a "living document" that undergoes official revisions.
  • Example: The terms and conditions for a service, an internal company policy, or a set of technical standards that are periodically updated. The ObjectId always points to the current, authoritative version.
• Control or ownership of the data may need to change hands.
  • Example: A project's master plan is notarized, and when the project lead changes, ownership of the notarization object is transferred to the new lead.