Credentials Attestation Service (CAS) is an infrastructure public good for making attestations onchain or offchain about anything.
Public Good. Open-Source. Permissionless. Token-Free.
Easily start building with others on mainnet, leading L2s, and various testnets.
attestations made
unique attesters
recipients
Discover the potential of blockchain attestations
Digital, physical, agent identities
Things you say online
What you own
What you care about
Your trust and credibility
Your skills and badges
What you have access to
Credit scores and financial health
Verified signatures on chain
The origination of anything
CAS works with only two smart contracts. One to register an attestation schema, and another to make attestations on Schemas. Elegantly simple. Limitless possibility.
struct SchemaRecord {
// A unique identifier of the schema.
bytes32 uid
// Optional schema resolver contract.
address resolver
// Whether the schema allows revocations explicitly.
bool revocable
// Custom specification of the schema.
string schema
}
struct Attestation {
// A unique identifier of the attestation.
bytes32 uid
// A unique identifier of the schema.
bytes32 schema
// The UID of the related attestation.
bytes32 refUID
// The time when the attestation was created.
uint64 time
// The time when the attestation expires.
uint64 expirationTime
// The time when the attestation was revoked.
uint64 revocationTime
// The recipient of the attestation.
address recipient
// The attester/sender of the attestation.
address attester
// Whether the attestation is revocable.
bool revocable
// Custom attestation data.
bytes data
}
Building the Future of Trust on the Blockchain
Built on blockchain technology for maximum security, ensuring tamper-proof attestations and verified data integrity.
Learn MoreLightning-fast attestation processing with optimized smart contracts and efficient verification systems.
Learn MoreYour data remains confidential with advanced encryption and selective disclosure protocols.
Learn MoreComprehensive Attestation Solutions for Every Need
Secure and verifiable blockchain attestations with real-time validation
Seamlessly integrate with existing blockchain infrastructure
Deploy across multiple blockchain networks
Instant verification with cryptographic proof
Flexible and scalable attestation solutions with enhanced privacy
Instant verification and processing
Optimize costs with selective onchain anchoring
Simple API integration with existing systems
Simple API with comprehensive documentation and examples to get you started quickly
Built on Ethereum's battle-tested security infrastructure
Deploy and verify attestations across multiple blockchain networks
Experience the power of blockchain attestations
Trusted by leading companies worldwide
"CAS has transformed how we handle digital identity verification. The integration was seamless and the results were immediate."
"The scalability and security features of CAS have helped us expand our blockchain operations significantly."
"The developer experience is outstanding. Documentation is clear, and the support team is always helpful."
"CAS has revolutionized our verification process. The multi-chain support is exactly what we needed."
Trusted by innovative companies worldwide
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Everything you need to know about CAS
An attestation is a claim made by an entity about another entity or itself. In the context of CAS, it's a verifiable statement stored on the blockchain that can represent any type of information or certification.
CAS implements advanced encryption protocols and allows for both on-chain and off-chain attestations. Users have complete control over their data and can choose what information to make public while keeping sensitive data private.
CAS supports multiple networks including Ethereum mainnet, leading L2s like Optimism and Arbitrum, and various testnets. This multi-chain approach ensures flexibility and accessibility for all users.
Getting started with CAS is simple. You can begin by exploring our documentation, connecting your wallet, and creating your first attestation. Our developer-friendly API and SDKs make integration straightforward.
Have questions about CAS or need help with integration? Our blockchain experts are here to help you succeed.
24/7 dedicated developer support
Priority response for enterprise