Signer Type

signer is a built-in Move type. A signer represents a capability that allows its holder to act on behalf of a specific address. Conceptually, the native implementation can be thought of as:

struct signer has drop { a: address }

A signer holds the address which signed the transaction being executed.

Comparison to address

A Move program can freely create any address value without special permission by using address literals:

let a1 = @0x1;
let a2 = @0x2;
// ... and so on for every other possible address

However, creating a signer value is restricted. A Move program cannot arbitrarily create a signer for any address. Instead, a signer can only be obtained through entry functions that are invoked as part of a transaction signed by the corresponding address.

entry fun example(s: signer) {
    /// Do something with signer
}

Warning

Only one signer can be passed to an entry function, representing the address that signed the transaction. Attempting to pass multiple signers or create signers for arbitrary addresses will result in a compilation error.

Note

In an EVM context, the signer corresponds to the tx.origin value.