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LSP6 - Key Manager

Standard Document

Introduction​

An LSP0ERC725Account on its own comes with limited usability. Since it is an owned contract, only the account's owner can write data into it or use it to interact with other smart contracts.

Here comes the Key Manager. A smart contract that controls a LSP0ERC725Account, acting as its new owner. It functions as a gateway for the account contract and allows not only one main contract owner but multiple controllers to interact with the LSP0ERC725Account.

What is a "controller"?

in the LSP6 Key Manager, the term "controller" refers to a permissioned address. These addresses have permissions that allow them to perform certain actions on the LSP0ERC725Account linked with the Key Manager (e.g., setting data or transferring LYX from the account).

Controllers can be Externally Owned Accounts (EOA) or smart contracts. The Key Manager will allow or restrict access based on the permissions set for the calling address.

Controllers can interact directly with the Key Manager or sign messages that can then be executed by any other parties (such as users or relay services).

❌   Without a Key Manager, only the LSP0ERC725Account's owner can use its Account.

✅   With a Key Manager attached to an LSP0ERC725Account, other addresses (EOAs or contracts) can use an Account on behalf of its owner.

LSP6 Key Manager overview allowed

LSP6 Key Manager overview not allowed

Permissions for addresses are not stored on the Key Manager. Instead, they are stored inside the data key-value store of the LSP0ERC725Account linked to the Key Manager. This way, it is possible to easily upgrade the Key Manager without resetting all the permissions again.


Permissions​

tip

You can use the encodePermissions(...) and decodePermissions(...) functions from the erc725.js tool to easily encode and decode permissions values or combine multiple permissions together.

Best Practices

While the Key Manager allows for a very fine-grained control over the Universal Profile (eg: CALL permission combined with AllowedCalls, SETDATA permission combined with AllowedERC725YDataKeys), it also allows for a very coarse-grained control over the Universal Profile, due to the SUPER permissions. This makes the Key Manager very flexible, but that flexibility comes with a slightly higher responsibility from the users.

Good practices:

  1. Split the permissions over the Universal Profile accross different devices, hardware wallets or a combination of both.
  2. Make sure to double or triple check when granting permissions to 3rd parties (other Universal Profiles, DApps, etc.).

LSP6 permissions

Click on the toggles below to learn more about the features enabled by each permission.

CHANGEOWNER - Allows changing the owner of the controlled contract

value = 0x0000000000000000000000000000000000000000000000000000000000000001

The CHANGEOWNER permission enables to change the owner of the linked ERC725Account. Using this permission, you can easily upgrade the LSP6KeyManager attached to the Account by transferring ownership to a new Key Manager.

ADDCONTROLLER - Allows giving permissions to new controller addresses.

value = 0x0000000000000000000000000000000000000000000000000000000000000002

The ADDCONTROLLER permission enables to grant permissions to new addresses that did not have any permissions before. This allows to add new permissioned addresses (controllers) that can then interact with or use the linked ERC725Account.

The ADDCONTROLLER permission is needed to:

  • Give a new address some permission(s) by setting its permissions under AddressPermissions:Permissions:<controller-address> (this is also refered to "adding a new controller")
  • Add a new controller address in the list of AddressPermissions[index] at a specific index.
  • Increase the length of the AddressPermissions[] Array length (to describe that a new controller has been added).

ADD Permissions

EDITPERMISSIONS - Allows changing existing permissions of controllers.

value = 0x0000000000000000000000000000000000000000000000000000000000000004

Caution:

Be aware that a controller with EDITPERMISSIONS can also edit its own permissions!

This permission allows for editing permissions of any controller (permissioned address) that has some permissions already set on the ERC725Account (including itself, see warning above).

The EDITPERMISSIONS is also needed to:

  • 🗑️ Remove a controller from the list of AddressPermissions[], meaning:
    • removing the controller address at a specific index in AddressPermissions[index]
    • decreasing the AddressPermissions[] Array length (to describe that a controller has been removed).
  • 🖊️ Edit an entry in the AddressPermissions[index] Array, meaning changing the address stored at a specific index.

EDIT Permissions

Bear in mind that the behavior of EDITPERMISSIONS slightly varies depending on the new permissions value being set (see figure below).

EDIT Permissions

ADDEXTENSIONS - Allows adding new extension contracts on the linked ERC725Account.

value = 0x0000000000000000000000000000000000000000000000000000000000000008

The ADDEXTENSIONS permission enables the addition of new LSP17 extension contracts for specific function selectors to be called when the account is called with a function that does not exist natively in its public interface. The fallback function of the linked ERC725Account will handle the call to the extension set for the function selector being called.

CHANGEEXTENSIONS - Allows editing the address for an extension contract on the linked ERC725Account.

value = 0x0000000000000000000000000000000000000000000000000000000000000010

The CHANGEEXTENSIONS permission enables editing LSP17 extension contract addresses for function selectors already set in the account. The LSP17 extension will be called when the account is called with a function that does not exist natively in its public interface. The fallback function of the linked ERC725Account will handle the call to the extension set for the function selector being called.

ADDUNIVERSALRECEIVERDELEGATE - Allows adding new LSP1UniversalReceiverDelegate contracts addresses.

value = 0x0000000000000000000000000000000000000000000000000000000000000020

The ADDUNIVERSALRECEIVERDELEGATE permission enables to add new LSP1UniversalReceiverDelegate extension contracts for specific Type IDs when no contracts extension was initially set up for a specific Type ID.

See LSP1 Universal Receiver > extension for more details.

NB this permission also enables to set the address of the default LSP1UniversalReceiverDelegate contract under the LSP1UniversalReceiverDelegate data key if no address was set in the first place.

CHANGEUNIVERSALRECEIVERDELEGATE - Allows editing LSP1UniversalReceiverDelegate contracts addresses.

value = 0x0000000000000000000000000000000000000000000000000000000000000040

The CHANGEUNIVERSALRECEIVERDELEGATE permission enables two things:

  1. edit the address of the default LSP1UniversalReceiverDelegate contract (linked under the LSP1UniversalReceiverDelegate data key).
  2. edit the addresses of the LSP1UniversalReceiverDelegate extension contracts linked to specific Type IDs.

See LSP1 Universal Receiver > extension for more details.

REENTRANCY - Allows reentering during an execution

value = 0x0000000000000000000000000000000000000000000000000000000000000080

The permission REENTRANCY enables a controller to execute a payload during the execution of another payload.

Depending on if the controller is an EOA or a contract:

  • A contract would reenter by using execute(..)
  • an EOA would do that through executeRelayCall(..).

Example:

One of the best uses for this permission is the following scenario:

  1. The ERC725Acccount linked to the Key Manager makes an external call to a contract A.
  2. Contract A will make some internal updates using the received data.
  3. The contract A will then call back the ERC725Account (via the Key Manager) with another payload that will update the account storage.

REENTRANCY Permission 1 REENTRANCY Permission 2

In order for that interaction to happen the contract A must have the REENTRANCY permission.

TRANSFERVALUE - Allows to transfer native tokens from the linked ERC725Account's balance with restrictions.

value = 0x0000000000000000000000000000000000000000000000000000000000000200

The TRANSFERVALUE permission enables to transfer the native tokens from the linked ERC725Account's balance with restrictions.

  1. to specific addresses (EOAs or contracts).
  2. to contracts implementing specific type of interfaces standards, that can be detected using ERC165 interfaces IDs.

Such restrictions can be applied using the LSP6 data AddressPermissions:AllowedCalls:<address>, where <address> is the address of the controller that has the TRANSFERVALUE permission.


Note: For simple native token transfers, no data ("") should be passed to the fourth parameter of the execute function of the Account contract. For instance: account.execute(operationCall, recipient, amount, "")

The caller will need the permission CALL to send any data along the LYX transfer.

CALL - Allows to use the linked ERC725Account to interact with contracts with restrictions.

value = 0x0000000000000000000000000000000000000000000000000000000000000800

The CALL permission enables to use the linked ERC725Account to call functions on contracts deployed on the network with restrictions.

  1. to specific contract addresses (contracts).
  2. to contracts implementing specific type of interfaces standards, that can be detected using ERC165 interfaces IDs.

It uses the CALL opcode, which allows to change states on the called contract.

STATICCALL - Allows calling other contracts through the controlled contract with restrictions

value = 0x0000000000000000000000000000000000000000000000000000000000002000

This permission enables the ERC725Account linked to Key Manager to make external calls to contracts while disallowing state changes at the address being called.

It uses the STATICCALL opcode when performing the external call.

NB: If any state is changed at a target contract through a STATICCALL, the call will revert silently.

DELEGATECALL - Allows delegate calling other contracts through the controlled contract with restrictions

value = 0x0000000000000000000000000000000000000000000000000000000000008000

This permission allows executing code and functions from other contracts in the UP context.

danger

DELEGATECALL is currently disallowed (even if set on the KeyManager) because of its dangerous nature, as vicious developers can execute some malicious code in the linked Account contract.

DEPLOY - Allows deploying other contracts through the controlled contract

value = 0x0000000000000000000000000000000000000000000000000000000000010000

The permission DEPLOY enables the controller to use the linked ERC725Account to deploy new smart contracts (the linked account will act as the deployer of the new contract).

Developers should provide the contract's bytecode to be deployed in the payload (ABI-encoded) passed to the Key Manager.

Both the CREATE or CREATE2 opcodes can be used to deploy a contract.

SETDATA - Allows setting data on the controlled contract with restrictions

value = 0x0000000000000000000000000000000000000000000000000000000000040000

The permission SETDATA allows a controller to write any form of data in the ERC725Y data key-value store of the linked ERC725Account.

However, this permission restricts the controller to set data for only specific data keys set via allowed ERC725Y Data Keys

info

A controller with permission SETDATA cannot set or edit data keys related to:

  • permissions: requires the permission of ADDCONTROLLER or EDITPERMISSIONS.
  • LSP1 data keys: requires the permission of ADDUNIVERSALRECEIVERDELEGATE or CHANGEUNIVERSALRECEIVERDELEGATE.
  • LSP17 data keys: requires the permission of ADDEXTENSIONS or CHANGEEXTENSIONS.
ENCRYPT: Allows encrypting data or messages on behalf of the controlled account

value = 0x0000000000000000000000000000000000000000000000000000000000080000

Developers can use the ENCRYPT permission to encrypt data or messages, for instance for private messaging.

DECRYPT: Allows decrypting data or messages on behalf of the controlled account

value = 0x0000000000000000000000000000000000000000000000000000000000100000

Developers can use the DECRYPT permission to decrypt data or messages, for instance for private messaging.

SIGN: Allows signing on behalf of the controlled account, for example for login purposes

value = 0x0000000000000000000000000000000000000000000000000000000000200000

The permission SIGN enables a controller to authenticate on behalf of the UP. It can be used primarily in Web 2.0 apps to sign login messages.

note

When deployed with our lsp-factory.js tool, the Universal Profile owner will have all the permissions above set by default.

SUPER Permissions​

The super permissions grant the same permissions as their non-super counterparts, with the difference being that the checks on restrictions for Allowed Calls and Allowed ERC725Y Data Keys are skipped.

The skip allows for cheaper transactions, whether these restrictions are set or not.

SUPER_TRANSFERVALUE

value = 0x0000000000000000000000000000000000000000000000000000000000000100

Same as TRANSFERVALUE, but allowing to send native tokens to any address (EOA or contract). This will also not check for Allowed Calls when transferring value to contracts.

SUPER_CALL

value = 0x0000000000000000000000000000000000000000000000000000000000000400

Same as CALL, but it allows interacting with any contract. This will not check if the controller has any Allowed Calls restrictions set.

SUPER_STATICCALL

value = 0x0000000000000000000000000000000000000000000000000000000000001000

Same as STATICCALL, but it allows interacting with any contract. This will not check if the controller has any Allowed Calls restrictions set.

SUPER_DELEGATECALL

value = 0x0000000000000000000000000000000000000000000000000000000000004000

Same as DELEGATECALL, but allows interacting with any contract. This will not check if the controller has any Allowed Calls restrictions set.

SUPER_SETDATA

value = 0x0000000000000000000000000000000000000000000000000000000000020000

Same as SETDATA, but allowing to set any ERC725Y data keys. This will not check for Allowed ERC725Y Data Keys if caller has any restrictions.

caution

Use with caution: If the controller address has Allowed Calls or Allowed ERC725Y Data Keys restrictions set, they will be ignored.

Combining Permissions​

Permissions can be combined if a controller needs more than one permission. To do so:

  1. calculate the sum of the decimal value of each permission.
  2. convert the result back into hexadecimal.
Example
permissions: CALL + TRANSFERVALUE

0x0000000000000000000000000000000000000000000000000000000000000800 (2048 in decimal)
+ 0x0000000000000000000000000000000000000000000000000000000000000200 (512)
---------------------------------------------------------------------
= 0x0000000000000000000000000000000000000000000000000000000000000a00 (= 2560)

Retrieving list of controllers​

tip

The convenience function getData(...) from erc725.js will return you the whole list of controllers when providing the AddressPermission[] array data key as a parameter.

You can obtain the list of controllers that have some permissions on the linked ERC725Account by reading the AddressPermission[] data key via getData(...).

  • key: 0xdf30dba06db6a30e65354d9a64c609861f089545ca58c6b4dbe31a5f338cb0e3
  • value return: the total number of address that have some permissions set (= array length)

Each controller can be retrieved by accessing each index in the array (see LSP2 > Array docs and LSP2 > Array Standard specs for more detailed instructions).

{
"name": "AddressPermissions[]",
"key": "0xdf30dba06db6a30e65354d9a64c609861f089545ca58c6b4dbe31a5f338cb0e3",
"keyType": "Array",
"valueType": "address",
"valueContent": "Address"
}

AddressPermissions array - list of addresses with permissions

example:

if the AddressPermission[] array data key returns 0x0000000000000000000000000000000000000000000000000000000000000004 (array length = 4), each controller can be obtained by reading the value under the following data keys:

  • 0xdf30dba06db6a30e65354d9a64c6098600000000000000000000000000000000: 1st controller (array index 0 = AddressPermissions[0])
  • 0xdf30dba06db6a30e65354d9a64c6098600000000000000000000000000000001: 2nd controller (array index 1 = AddressPermissions[1])
  • 0xdf30dba06db6a30e65354d9a64c6098600000000000000000000000000000002: 3rd controller (array index 2 = AddressPermissions[2])
  • 0xdf30dba06db6a30e65354d9a64c6098600000000000000000000000000000003: 4th controller (array index 3 = AddressPermissions[3])

Types of permissions​

Permission TypeDescriptionbytes32 data key
Address Permissionsdefines a set of permissions for a controller.0x4b80742de2bf82acb3630000<address>
Allowed Callsdefines a set of interactions (action + address + function + standard) allowed for a controller.0x4b80742de2bf393a64c70000<address>
Allowed ERC725Y Data Keysdefines a list of ERC725Y Data Keys a controller is only allowed to set via setData(...) on the linked ERC725Account.0x4b80742de2bf866c29110000<address>

See LSP6 for more details

The values set under these permission data keys MUST be of the following format to ensure correct behavior of these functionalities.

  • Address Permissions: a bytes32 value.
  • Allowed Calls: a CompactBytesArray of the tuple (bytes4,address,bytes4,bytes4).
  • Allowed ERC725Y Data Keys: a CompactBytesArray of bytes, containing values from bytes1 to bytes32.
caution

To add or remove entries in the list of allowed calls or ERC725Y Data Keys, the whole compact bytes array should be encoded again and reset. Each update overrides the entire previous state. Note that this process can be expensive in gas, depending on the total number of allowed calls.

Address Permissions​

A controller can hold one (or more) permissions, enabling it to perform multiple "actions" on an ERC725Account. Such "actions" include setting data, calling other contracts, transferring native tokens, etc.

To grant permission(s) to a controller, set the following data key-value pair in the ERC725Y storage of the ERC725Account linked to the Key Manager.

  • key: 0x4b80742de2bf82acb3630000<address>
  • value: one of the available permission below. To give multiple permission, see the Combining permissions section.

NB: remember to remove the 0x prefix in the <address> field above.

{
"name": "AddressPermissions:Permissions:<address>",
"key": "0x4b80742de2bf82acb3630000<address>",
"keyType": "MappingWithGrouping",
"valueType": "bytes32",
"valueContent": "BitArray"
}

Address Permissions range

danger

Granting permissions to the linked ERC725Account itself is dangerous!

A caller can craft a payload via ERC725X.execute(...) to be sent back to the KeyManager, leading to potential re-entrancy attacks.

Such transaction flow can lead an initial caller to use more permissions than allowed initially by re-using the permissions granted to the linked ERC725Account's address.

caution

Each permission MUST be exactly 32 bytes long and zero left-padded:

  • 0x0000000000000000000000000000000000000000000000000000000000000008 ✅
  • 0x0800000000000000000000000000000000000000000000000000000000000000 ❌

For instance, if you try to set the permission TRANSFERVALUE for an address as 0x08, this will be stored internally as 0x0800000000000000000000000000000000000000000000000000000000000000.

Ensure the bytes32 value set under the permissions are correct according to these rules, to prevent incorrect or unexpected behaviour and errors.


Allowed Calls​

You can restrict a controller permission (CALL/TRANSFERVALUE/etc..) to be valid with specific:

Call Types

Below is the list of Call Types and their possible combination.

call typevalue
TRANSFERVALUE0x00000001
CALL0x00000002
STATICCALL0x00000004
DELEGATECALL0x00000008
Addresses
AddressMeaning
0xffffffffffffffffffffffffffffffffffffffffInteraction with any address is allowed.
Other addressesInteraction with a specific address is allowed.
Standards

These contracts MUST implement the ERC165 standard to be able to detect their interfaces.

Interface IDMeaning
0xffffffffInteraction with any standard is allowed.
Specific interfacesInteraction with a specific standard is allowed.
Functions
Function SelectorMeaning
0xffffffffInteraction with any function is allowed.
Other function selectorsInteraction with a specific function is allowed.

To restrict a controller to a specific set of calls, set the following data key-value pair in the ERC725Y storage of the ERC725Account linked to the Key Manager.

  • key: 0x4b80742de2bf393a64c70000<controller-address>
    • where <address> is the controller address
  • possible values:
    • (bytes4,address,bytes4,bytes4)[CompactBytesArray]: a CompactBytesArray of tuple which described the allowed call (call type + address + standard + function). See details below for each element of the tuple.
    • 0x (empty): if the value is an empty byte (= 0x), the controller is not allowed to interact with any functions, address or standards (= all calls are disallowed).

Each entry in the CompactBytesArray is an Allowed Call. An Allowed Call is represented by a tuple of (bytes4,address,bytes4,bytes4), where each value in the tuple corresponds to the following:

  1. bytes4 (call type) = the call type(s) allowed for this allowed call (TRANSFERVALUE, CALL, STATICCALL and DELEGATECALL).
  2. address (address) = the address of an EOA or a contract. Can be used to restrict only to interact with a specific address.
  3. bytes4 (standard) = the ERC165 interface ID of a standard interface. Can be used to specify the "type of contract" allowed to interact with.
  4. bytes4 (function) = a bytes4 function selector. Can be used to restrict a controller to call only a specific function on a contract.

If you want to have multiple different interactions, you MUST add each of the desired interaction in the CompactBytesArray of AllowedCalls. Keep in mind that the length for each element in the CompactBytesArray must be 32 = 0x0020, because the tuple (bytes4,address,bytes4,bytes4) makes up 32 bytes in total.

Example 1: allow only to CALL a specific LSP0 at a specific address

To allow a controller to only do CALL to any function on a LSP0ERC725Account (interface ID 0x3e89ad98) deployed at address 0xCA41e4ea94c8fA99889c8EA2c8948768cBaf4bc0, the following value for the CompactBYytesArray of allowed calls will be used:

0x002000000002CA41e4ea94c8fA99889c8EA2c8948768cBaf4bc03e89ad98ffffffff

Where:

  • element length: 0x0020 (= 32 bytes)
  • Permission: CALL, 0x00000002;
  • Standard: LSP0 interface ID = 0x3e89ad98;
  • Address: 0xCA41e4ea94c8fA99889c8EA2c8948768cBaf4bc0;
  • Function: any;
Example 2: allow multiple interactions of different types

Consider the scenario where you want to give the following permissions to a controller:

  • allow to CALL any functions (as well as transferring value TRANSFERVALUE) to a LSP0 contract deployed at address 0xCA41e4ea94c8fA99889c8EA2c8948768cBaf4bc0.
  • allow to CALL only the transfer(address,address,uint256,bool,bytes) function on the contract deployed at address 0xF70Ce3b58f275A4c28d06C98615760dDe774DE57.
  • allow to do STATICCALLs to any functions on the contract deployed at address 0xd3236aa1B8A4dDe5eA375fd1F2Fb5c354e686c9f.

The CompactBytesArray of allowed calls for this controller will be composed of the following entries:

  • AllowedCalls[0] = the 1st value in the CompactBytesArray will be 0x002000000002CA41e4ea94c8fA99889c8EA2c8948768cBaf4bc03e89ad98ffffffff.

    • Permission: CALL and TRANSFERVALUE, 0x00000003;
    • Standard: LSP0 interface ID = 0x3e89ad98;
    • Address: 0xCA41e4ea94c8fA99889c8EA2c8948768cBaf4bc0;
    • Function: any;
  • AllowedCalls[1] = the 2nd value in the CompactBytesArray will be 0x002000000003F70Ce3b58f275A4c28d06C98615760dDe774DE57ffffffff760d9bba.

    • Permission: CALL, 0x00000002;
    • Standard: any;
    • Address: 0xF70Ce3b58f275A4c28d06C98615760dDe774DE57;
    • Function: transfer(address,address,uint256,bool,bytes), 0x760d9bba;
  • AllowedCalls[2] = the 3rd value in the CompactBytesArray will be 0x002000000004d3236aa1B8A4dDe5eA375fd1F2Fb5c354e686c9fffffffffffffffff

    • Permission: STATICCALL, 0x00000004;
    • Standard: any;
    • Address: 0xd3236aa1B8A4dDe5eA375fd1F2Fb5c354e686c9f;
    • Function: any;

A CompactBytesArray for these 3 interactions would look like this: 0x002000000003CA41e4ea94c8fA99889c8EA2c8948768cBaf4bc03e89ad98ffffffff002000000002F70Ce3b58f275A4c28d06C98615760dDe774DE57ffffffff760d9bba002000000004d3236aa1B8A4dDe5eA375fd1F2Fb5c354e686c9fffffffffffffffff

{
"name": "AddressPermissions:AllowedCalls:<address>",
"key": "0x4b80742de2bf393a64c70000<address>",
"keyType": "MappingWithGrouping",
"valueType": "(bytes4,address,bytes4,bytes4)[CompactBytesArray]",
"valueContent": "(BitArray,Address,Bytes4,Bytes4)"
}

LSP6 Allowed Calls Overview

danger

Allowing a specific standard does not offer security over the inner workings or the correctness of a smart contract. It should be used more as a "mistake prevention" mechanism than a security measure.

info

If no Allowed Calls are set (0x), a controller cannot interact with any address nor transfer any value (Contract or EOA).


Allowed ERC725Y Data Keys​

If a controller is allowed to SETDATA on an ERC725Account, it is possible to restrict which data keys this address can set or update.

To restrict a controller to only be allowed to set the key LSP3Profile (0x5ef83ad9559033e6e941db7d7c495acdce616347d28e90c7ce47cbfcfcad3bc5), the following data key-value pair can be set in the ERC725Y contract storage. Encode data as a CompactBytesArray.

  • key: 0x4b80742de2bf866c29110000<address>
  • value(s): 0x00205ef83ad9559033e6e941db7d7c495acdce616347d28e90c7ce47cbfcfcad3bc5
ERC725Y Data Keys: fixed-size vs dynamic-size

Introduction (summary) You can set 2 types of ERC725Y Data Keys:

  • Fixed-size Data Keys

A fixed-size Data Key is a data key with a fixed length of 32 bytes. If a controller address has a fixed-size allowed ERC725Y data key set, then that controller can only change the value of that specific fixed-size data key.

  • Dynamic-size Data Keys

A dynamic-size Data Key is a data key with a variable length from 1 byte up to 31 bytes. If a controller has a dynamic-size allowed ERC725Y data key set, then that controller can change any data key that starts with the dynamic-size data key.

Examples:

  • Fixed-size Data Keys

Let's imagine the following situation, you set an Allowed ERC725Y fixed-size Data Key (e.g. 0x5ef83ad9559033e6e941db7d7c495acdce616347d28e90c7ce47cbfcfcad3bc5) for a controller (e.g. Alice). With that setup you allowed Alice to update only the value of the Allowed ERC725Y Data Key.

LSP6 Allowed ERC725Y Data Keys, Fixed-Size Key

  • Dynamic-size Data Keys

Let's imagine the following situation: You set an Allowed ERC725Y dynamic-size Data Key (e.g., 0xbeefbeefbeefbeef) for a controller (e.g., Bob). With that setup you allowed Bob to set any Data Key that starts with 0xbeefbeefbeefbeef.

E.g:

  • 0xbeefbeefbeefbeefcafecafecafecafecafecafecafecafecafecafecafecafe
  • 0xbeefbeefbeefbeef0000000000000000000000000000000000000000c629dfa8
  • 0xbeefbeefbeefbeef000000000000000000000000000000000000000000001253

LSP6 Allowed ERC725Y Data Keys, Dynamic-Size Key

Combining multiple ERC725Y Data Keys

If you want to have multiple different ERC725Y data keys allowed, you MUST add each of the desired data keys to a CompactBytesArray.

E.g.:

  • 0x5ef83ad9559033e6e941db7d7c495acdce616347d28e90c7ce47cbfcfcad3bc5 (length: 32 bytes = 0x0020)
  • 0x5ef83ad9559033e6e941db7d7c495acd (length: 16 bytes = 0x0010)
  • 0xbeefbeef (length: 4 bytes = 0x0004)

A CompactBytesArray for these 3 different ERC725Y Data Keys would look like this: 0x00205ef83ad9559033e6e941db7d7c495acdce616347d28e90c7ce47cbfcfcad3bc500105ef83ad9559033e6e941db7d7c495acd0004beefbeef

{
"name": "AddressPermissions:AllowedERC725YDataKeys:<address>",
"key": "0x4b80742de2bf866c29110000<address>",
"keyType": "MappingWithGrouping",
"valueType": "bytes32[CompactBytesArray]",
"valueContent": "Bytes32"
}

Below is an example use case. An ERC725Account can allow some applications to add/edit informations on its storage via setData(...). The account can restrict such Dapps and protocols to edit the data keys that are only relevant to the logic of their applications.

LSP6 Allowed ERC725YDataKeys overview

As a result, this provide context for the Dapp on which data they can operate on the account, while preventing them to edit other information, such as the account metadata, or data relevant to other dapps.

LSP6 Allowed ERC725YDataKeys overview

LSP6 Allowed ERC725YDataKeys overview

LSP6 Allowed ERC725YDataKeys overview

info

If no Allowed ERC725Y Data Keys are set, the controller cannot set any value for any key.


Types of Execution​

There are 3 ways to interact with the ERC725Account linked with the Key Manager.

  • direct execution: the controller is the caller (msg.sender) and sends a payload to the Key Manager directly (= abi-encoded function call on the linked ERC725Account) to the KeyManager via execute(...).
  • relay execution: a controller A signs a payload and an executor address B (e.g. a relay service) executes the payload on behalf of the signer via executeRelayCall(...).
  • LSP20-CallVerification execution: Interaction with the ERC725Account can be done directly, in accordance with the LSP20-CallVerification standard. The LSP6 Key Manager supports this standard, allowing anyone to call the LSP0ERC725Account. If the caller is not the owner of the ERC725Account, the call will be forwarded to the LSP20 functions of the Key Manager. These functions will verify the necessary permissions and emit the relevant event.

The main difference between direct vs relay vs LSP20-CallVerification execution is that with direct execution, the controller address is the actual address making the request + paying the gas cost of the execution. With relay execution, a signer address (a controller) can interact with the ERC725Account without paying a gas fee. And with LSP20-CallVerification execution, calls can be made directly to the ERC725Account, with permissions verified by the LSP20 functions of the Key Manager.

Direct vs Relay Execution

Gas-Less Transactions​

Best Practices

While gas-less transactions / relay-execution is a very convenient way of using your Universal Profile to surf the blockchain, it comes with its risks.

  • A relay call does not enforce a gas price to execute a transaction, meaning a Relay Service can potentially send your transaction with a lower gas price in order to cut costs which might take a long time to execute.
  • A Relay Service can also frontrun your transaction.

Best practices:

  • Make sure to only use audited, transparent, community trusted Relay Services that have passed the test of time.
  • Stay away from Relay Services that try to acquire users by offering cheaper prices. In the end any Relay Service must have a business model in order to work. If it does not profit from users it profits from other ways, might be shady or not.

Relay execution enables users to interact with smart contracts on the blockchain without needing native tokens to pay for transaction fees. This allows a better onboarding experience for users new to cryptocurrencies and blockchain.

Relay execution minimizes UX friction for dapps, including removing the need for users to worry about gas fee, or any complex steps needed to operate on blockchains (KYC, seedphrases, gas).

Dapps can then leverage the relay execution features to create their own business model around building their own relay service, smart contracts solution on top of the Key Manager to pay with their tokens, or agree with users on payment methods including subscriptions, ads, etc ..

LSP6 Key Manager Relay Service

An essential aspect to consider in relay execution is the time validity of the execution signature. It's sometimes beneficial to limit the execution to be valid within a specific timeframe to prevent potential security risks. For example, if a user signs a relay transaction and the signature is stolen or compromised, the attacker could potentially use this signature indefinitely if there's no validity period set.

To mitigate such risks, adding an optional validity timestamp to the signature could mark the start date and expiry date of its effectiveness. Once the timestamp has passed, the signature is no longer valid, rendering the relay transaction unusable.

How to sign relay transactions?​

tip

You can use our library eip191-signer.js to make it easier to sign an EIP191 Execute Relay Call transaction.

See also our step by step Javascript guide to sign and execute relay transactions via the Key Manager.

Overview​

To obtain a valid signature that can be used by anyone to execute a relayed transaction (= meta transaction) on behalf of someone else, we must do the following:

  1. Gather 5 things:

      1. the payload (an abi-encoded function call) to be executed on the linked account.
      1. the chain id of the blockchain where the payload will be executed.
      1. the address of the LSP6KeyManager smart contract where the payload will be executed. d. the Key Manager nonce of the controller.
      1. the validityTimestamps, composed of 2 x uint128 concatenated together, where:

        4.1. the left-side uint128 corresponds to the timestamp from which the relay call is valid from.

        4.2. the right-side uint128 corresponds to the timestamp from which the relay call is valid until.

  2. Once you have gathered these 5 information, you must concatenate them all together.

  3. Then you must get the keccak256 hash of this data.

  4. After that you can sign the data to obtain a valid signature ready to be used via executeRelayCall(...).

Details​

The relay transactions are signed using the version 0 of EIP191. The relay call data that you want to sign MUST be the keccak256 hash digest of the following elements (bytes values) concatenated together.

0x19 <0x00> <KeyManager address> <LSP6_VERSION> <chainId> <nonce> <validityTimestamps> <value> <payload>
Message elementsDetails
0x19Byte used to ensure that the relay call signed data is not a valid RLP.
0x00The version 0 of EIP191.
KeyManager addressThe address of the Key Manager that will execute the relay call.
LSP6_VERSIONThe version of the Key Manager that will execute the relay call, as a uint256. (Current version of LSP6 Key Manager is 6)
chainIdThe chain id of the blockchain where the Key Manager is deployed, as uint256.
nonceThe unique nonce for the payload.
validityTimestampsTwo uint128 timestamps concatenated, the first timestamp determines from when the payload can be executed, the second timestamp delimits the end of the validity of the payload. If validityTimestamps is 0, the checks of the timestamps are skipped
valueThe amount of native tokens that will be transferred to the ERC725 Account linked to the Key Manager that will execute the relay call.
payloadThe payload that will be exeuted.

Out of order execution​

Since the Key Manager offers relay execution via signed message, it's important to provide security measurements to ensure that the signed message can't be repeated once executed. Nonces existed to solve this problem, but with the following drawback:

  • Signed messages with sequential nonces should be executed in order, meaning a signed message with nonce 4 can't be executed before the signed message with nonce 3. This is a critical problem which can limit the usage of relay execution.

Here comes the Multi-channel nonces which provide the ability to execute signed message with/without a specific order depending on the signer choice.

Signed messages should be executed sequentially if signed on the same channel and should be executed independently if signed on different channel.

  • Message signed with nonce 4 on channel 1 can't be executed before the message signed with nonce 3 on channel 1 but can be executed before the message signed with nonce 3 on channel 2.

LSP6 Key Manager Relay Service

Learn more about Multi-channel nonces usecases and its internal construction.

References​