> ## Documentation Index
> Fetch the complete documentation index at: https://docs.neuro-tech.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Cryptographic keys
> How cryptographic keys are used across the Neuro platform
Cryptographic keys are part of how Neuro protects identity, signatures, and trust across the platform.
They are used to establish and validate cryptographic identities, sign important platform objects, and protect the integrity of contracts, tokens, and ledger-backed events. Cryptographic identities in Neuro are based on a public-key algorithm, a public key, and a signature from a Trust Provider. The platform is designed so that cryptographic algorithms can evolve over time — rather than being permanently fixed into infrastructure.
## Why keys matter in Neuro
In Neuro, keys are not just a low-level implementation detail — they are part of the trust model itself.
Legal identities, smart contracts, token actions, and other important platform objects rely on cryptographic signatures. That allows the platform to provide integrity, authenticity, and traceability across domains. Neuro smart contract material explicitly states that contracts are signed using the cryptographic keys defined for the corresponding legal identities.
## Public keys and private keys
| | Role |
| --------------- | ---------------------------------------------------------------------------------------- |
| **Private key** | Used to create a signature. Stays with the client and does not leave the client device. |
| **Public key** | Used to validate that signature. Shared and referenced in identities and signed objects. |
Private keys should remain with the client — this is fundamental to how Neuro establishes trust in signed actions and identity-backed interactions.
## Why algorithm agility matters
One important idea in Neuro is that cryptographic algorithms should not be treated as permanent.
Long-lived systems must be able to change cryptographic algorithms over time, because every algorithm has a practical lifespan. That is why the platform emphasizes negotiable and replaceable cryptographic methods instead of locking core infrastructure to one fixed choice forever.
This is especially relevant for systems built to operate across years or decades — such as medical records systems, real estate registries, or critical infrastructure.
## Key takeaways
Understanding keys is not about memorizing algorithm details. It is about recognising that keys are central to:
* Identity
* Signatures
* Contract validity
* Token ownership and actions
* Ledger-backed verification
* Secure interoperability across domains
When you encounter keys in Neuro, you are encountering the trust foundation of the platform.
**Cryptographic keys are the foundation for trusted identity and signed actions in Neuro.**
## Further reading
Platform specification and standards
Neuron and associated technologies
Tutorials and implementation guides