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# EIP-1388: Attestation Issuers Management List Source

Author Weiwu Zhang, James Sangalli https://github.com/ethereum/EIPs/issues/1388 Stagnant Standards Track ERC 2018-09-08

### Introduction

In smart contracts, we will need methods to handle cryptographic attestations to a users identifier or abilities. Let’s say we have a real estate agent, KiwiRealtors, that provides an “expression of interest” function though a smart contract and requires the users to provide an attestation that they are a resident of New Zealand or Australia, as a legal requirement. This has actually happened in the New Zealand property market and it is the perfect example of a need to handle such attestations.

However, it is not practical for a smart contract to explicitly trust an attestation issuer. There are multiple issuers who can provide an attestation to a person’s residency - a local Justice of the Peace, the land title office, local police, passport authority etc. We envision a model where the effort to manage the list of qualified issuers is practically outsourced to a list.

Anyone can publish a list of issuers. Only the most trusted and carefully maintained lists gets popular use.

### Purpose

This ERC provides a smart contract interface for anyone to manage a list of attestation issuers. A smart contract would explicitly trust a list, and therefore all attestations issued by the issuers on the list.

### Draft implementation

    /* The purpose of this contract is to manage the list of attestation
* issuer contracts and their capacity to fulfill requirements
*/
contract ManagedListERC
{
/* a manager is the steward of a list. Only he/she/it can change the
* list by removing/adding attestation issuers to the list.

* An issuer in the list is represented by their contract
* addresses, not by the attestation signing keys managed by such a
* contract.
*/
struct List
{
string name;
string description; // short description of what the list entails
string capacity; // serves as a filter for the attestation signing keys
/* if a smart contract specifies a list, only attestation issued
* by issuers on that list is accepted. Furthermore, if that
* list has a non-empty capacity, only attestations signed by a
* signing key with that capacity is accepted. */

uint expiry;
}

// find which list the sender is managing, then add an issuer to it

//return false if the list identified by the sender doesn't have this issuer in the list

/* called by services, e.g. Kiwi Properties or James Squire */
/* loop through all issuer's contract and execute validateKey() on
* every one of them in the hope of getting a hit, return the
* contract address of the first hit. Note that there is an attack
* method for one issuer to claim to own the key of another which
* is mitigated by later design. */
//loop through the issuers array, calling validate on the signingKeyOfAttestation

/* for simplicity we use sender's address as the list ID,
* accepting these consequences: a) if one user wish to maintain
* several lists with different capacity, he or she must use a
* different sender address for each. b) if the user replaced the
* sender's key, either because he or she suspects the key is
* compromised or that it is lost and reset through special means,
* then the list is still identified by the first sender's
*/

function createList(List list) public;

/* replace list manager's key with the new key */
function replaceListIndex(List list, address manager) public returns(bool);

}