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How can an assistant act without your main key?
Bound delegated work by resource, action, duration and revocation.
A photo assistant should read this week's travel album and produce labels. It should not delete photos or read other albums. The task calls for limited access; handing over an account's main key may grant much more control than the task requires.
An authorization credential is material a service checks to determine access, such as an access token. “Token” here describes an access mechanism, not a traded asset.
Make permission specific
Specify the album, permitted actions, intended assistant, expiry and early termination. The resource service must enforce those limits. A consent screen saying “read only” cannot replace access checks.
OAuth provides a framework for limited access. Its scopes describe access ranges, while file boundaries, duration and revocation behavior need service-specific definitions. OAuth support does not imply permission at individual-file granularity. A DID does not imply that these features exist either.
Revocation has timing limits. Services may learn of a change at different times; short-lived credentials bound how long access lasts, while checking current status on each request can detect revocation sooner but adds a dependency on the checking service. Stopping future access cannot erase photos already copied.
Consider three moments: the task finishes, the assistant makes a mistake, or its credential leaks. Who can stop further work, and what data remains outside your control? Answering these questions does not require a blockchain.
Book and sources
This lesson develops the questions in Chapters 4–5 of 《区块链实战》 with later standards. It is not an excerpt.
Related patent
Blockchain delegation connects this concept to a disclosed technical design and its original patent record.
Why can a valid signature still be rejected?
In a delegation scheme that uses signatures, signature verification and permission checks answer different questions: was the transaction signed by a holder of the delegate key, and does the operation remain within the grant? The key can stay unchanged while its permission expires, runs out, or is revoked.
On-chain revocation must take effect under the chain's rules. When revocation and a delegated request are submitted together, the state used for execution matters; a later revocation does not reverse an already completed transaction. How can software act while your main key stays offline? follows a hypothetical task through grants, cumulative limits, and revocation, drawing on the disclosed blockchain delegation patent.
Check your understanding
Does revoking read access erase photos an assistant already downloaded?
No. Revocation can stop later requests where access checks enforce it; it cannot recall copied data.
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