About Sigma Auth
Sigma Auth, also known as Sigma Identity, is cryptographic identity infrastructure for people, applications, and AI agents. Identity is a key the holder controls, and signing in is a signature instead of a password.
Identity you hold, backup you can recover
Sigma Auth provides standard OAuth 2.0 sign-in backed by Bitcoin keypairs the user generates and holds. The hosted service adds encrypted cloud backup as a service: your identity keys are encrypted on your device before anything is uploaded, Sigma stores only the encrypted blob, and an OAuth account you already have (Google, GitHub) acts as the recovery handle that locates it. The server never holds a private key and cannot read a backup. The key backup docs cover the full model.
The same mechanism answers the Know Your Agent question for software that acts on its own behalf: an agent that can sign is an agent that can prove which identity it is and on whose authority it acts. The KYA explainer covers why that matters.
What lives where
sigmaidentity.com
The product home: documentation, integration guides, comparisons, pricing, and the company pages you are reading now. It serves no OAuth endpoints and issues no tokens.
auth.sigmaidentity.com
The OAuth 2.0 / OIDC server: authorization, token issuance, device flow, and agent authentication. Its machine-readable contract lives at auth.sigmaidentity.com/openapi.json.
Integrators point their applications at the auth server and read the docs here. The split is deliberate: the marketing site can change daily without touching the surface that issues tokens.
Published by Open Protocol Labs
Sigma Auth is built and operated by Open Protocol Labs, Inc., a company founded in 2023 that designs low-level open protocols on Bitcoin and builds the applications that put them to work. Kurt Wuckert Jr. is Chief Executive Officer and Luke Rohenaz is Chief Technology Officer. The company's broader portfolio, including 1Sat Ordinals, OrdFS, and the 1Sat Browser, lives at opl.dev.
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