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4. The UID & TxContext

Generating globally unique identifiers.

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Every new object obtains a `UID` generated from the transaction context (`object::new(ctx)`). The `TxContext` provides transaction metadata: sender address, epoch timestamp, and fresh ID entropy.

move
public fun create(ctx: &mut TxContext): Greeting {
    Greeting {
        id: object::new(ctx),
        text: std::string::utf8(b"Hello Sui"),
    }
}

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Check your understanding

1. How is a fresh UID created in a Sui Move function?
object::new(ctx)UID::generate()ctx.new_id()object::create()
2. What information does TxContext provide to smart contract functions?
Sender address, transaction digest, and fresh UID generation stateValidator private keysEVM gas priceBlock rewards

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