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Security · hard

45. Access Control: tx-sender vs contract-caller

Preventing intermediate phishing attacks.

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`tx-sender` is the original signer of the transaction. `contract-caller` is the immediate caller. Validating against `contract-caller` prevents malicious intermediary contracts from acting on behalf of users.

clarity
;; Secure authorization
(asserts! (is-eq contract-caller OWNER) (err u403))

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Check your understanding

1. What is the difference between tx-sender and contract-caller?
tx-sender is the originating tx signer; contract-caller is the immediate callerThey are always identicalcontract-caller is the minertx-sender is the contract
2. Why check contract-caller instead of tx-sender in sensitive administrative functions?
Prevents proxy contracts from spoofing administrative authorizationIt is cheapertx-sender is deprecatedRequired by LISP

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