[Forum post](https://forum.moonbeam.foundation/t/proposal-19-status-seconding-set-code-for-authormapping-randomness-and-xcmutils-precompiles/315)

## TL: DR
Sets a dummy code for AuthorMapping, Randomness and XcmUtils precompiles so smart contracts can more easily interact with them.

## Summary
Precompiles are system contracts that don't have any code in it. Therefore, `eth_getCode` returns `0x` or emtpy.

When smart contracts make calls to other contracts like `Contract.functionName` there is `code.length` check which fails. Consequently, smart contracts can't easily call/interact with precompiles.

By setting this dummy code (`0x60006000fd`, which is a basic revert opcode) smart contracts can now more easily interact with these precompiles.

## Proposal

Proposal #X19 with the following hash: *0x9e4ca11e73b4b33d47ceee3cae51326b5df3ffd91ee58c6c8866496b5e82ee66*

## Technical details:

The storage key for an address can be calculated using the following code:

```
const getStorageKey = async (address) => {
  let palletEncoder = new TextEncoder().encode('EVM');
  let palletHash = xxhashAsU8a(palletEncoder, 128);
  let storageEncoder = new TextEncoder().encode('AccountCodes');
  let storageHash = xxhashAsU8a(storageEncoder, 128);
  let assetAddress = new Uint8Array(hexToU8a(address));
  let addressHash = blake2AsU8a(assetAddress, 128);
  let concatKey = new Uint8Array([...palletHash, ...storageHash, ...addressHash, ...assetAddress]);

  return u8aToHex(concatKey);
};
```

The SCALE encoded call data is:

```
0x00050c11011da53b775b270400e7e61ed5cbc5a146ea70f53d5a3306ce02aaf97049cf181abbb77f5fe3a60fd004a7063f17f63dda0000000000000000000000000000000000000807181460006000fd11011da53b775b270400e7e61ed5cbc5a146ea70f53d5a3306ce02aaf97049cf181ac1c062eb3ecc887abc7fd90c52bc68420000000000000000000000000000000000000809181460006000fd11011da53b775b270400e7e61ed5cbc5a146ea70f53d5a3306ce02aaf97049cf181a5ae0b760b393d12e71ff11e979ba8fdc000000000000000000000000000000000000080c181460006000fd
```

You can find the code use to calculate the SCALE encoded call data [here](https://github.com/albertov19/PolkaTools/blob/main/setDummyCode.ts). 


- This proposal is about setting a dummy code for certain system contracts.
- Smart contracts need code to interact with other contracts, but these system contracts don't have any code.
- By setting this dummy code, smart contracts can now easily interact with these system contracts.
- The proposal has a specific hash number.
- There are technical details and code provided for those who want to know more.

#83 Set Code for AuthorMapping, Randomness and XcmUtils Precompiles

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