The OP Mainnet upgrade to the Bedrock release will take place on June 6, 2023 at 16:00 UTC! There will be 2-4 hours of downtime.
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Building Decentralized Identity Apps with Attestations


# About attestations

Attestations are signed statements about a person, entity, or thing, made by an individual, company, or organization and are one of the building blocks of decentralized identity.

Our journey towards decentralized identity begins with the AttestationStation, an attestation smart contract using the Ethereum Attestation Service standard (opens new window) for creating, verifying, and revoking on/off-chain attestations. You can think of the AttestationStation as a multiplayer database for streamlining the attestation process and enabling a robust web of trust on any OP Chain in the Superchain.

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# Benefits of using the AttestationStation

The AttestationStation makes it easy to sign any piece of data. In addition, here are a few key benefits:

  • Permissionless: The AttestationStation is a public contract, which means that it is not owned or controlled by any one person or organization. Anyone can use the contract to verify and attest anything.
  • Tooling: Indexing, various access-management integrations, and more are already available for the AttestationStation.

# Ideas

Are you inspired and don’t know what to build? We have a project idea list (opens new window). Do you have a good idea, but you know you’re not the right person to build it? Please open a PR on that list and suggest it.

# Privacy

Attestations create log entries that become part of the permanent record of the blockchain. Here are some best practices to avoid violating users’ privacy:

  • Obtain explicit consent from users for personal information. Clearly inform them what data is being collected, why it is being collected, and how it will be used.
  • Sensitive data should not be stored onchain, in any way. If you need a smart contract to verify it in the future, you can use the hash of the sensitive data rather than the data itself.
  • Even when storing sensitive data offchain, you need to ensure it is stored securely using encryption, proper authentication and authorization, etc.

# Common questions

Q: Are attestations replacements for verifiable credentials?

A: Attestations should not be viewed as a replacement for verifiable credentials or decentralized identifiers. Rather developers can use attestations to create decentralized identifiers (opens new window), credentials, claims, and more.

Q: Are attestations replacements for proof of personhood?

A: Attestations and the associated web of trust are complementary with proof of personhood like WorldID (opens new window) and similar solutions. Without proof of personhood, agents could sybil-attack the web of trust to build their reputation. On the other hand web of trust extends proof of personhood to confer more information about the person you're interacting with which is critical in governance and other use-cases that require knowledge of the person's reputation.

Q: Why attestations instead of soulbound / non-transferable tokens?

A: Attestations have two key benefits over soulbound / non-transferable tokens: flexibility of whether the attestations is onchain or offchain and composability. While there is a canonical decentralized schema registry for attestations (opens new window), there is no central registry or specification for soulbound / non-transferable tokens which can lead to poor interoperability between systems and protocols.