Account

Account Permission System

Overview

The account-permission system of IOST is based on the mechanism of public-private key pairs. By setting up owner key and active key, users may conveniently manage multiple account systems, and at the same time, set up new permission and secret weight at will. This enables many customized management functionalities.

Basics of Account System

An IOST account is created with ID and permissions. An account may have multiple permissions, and has owner and active permissions at the very least. Each permission will register multiple items, with one item being a base58 encoded public key, or a permission pair from another account.

Permission pair can be a string of account_name@permission_name

Each item has a certain weight; correspondingly, each permission has a threshold. When a transaction item has a weight larger than the threshold, the transaction assumes that permission.

The method of checking item ownership is by checking whether the transaction signatures contain the signature for that certain item's public key (when the item is a public key), or recursively check if the transaction contains the item's account-permission pair (when the item is an account-permission pair).

Generally, smart contracts will present their account ID and permission ID when validating for permissions. The system will check the transaction's signatures, calculate the items' weights and, when the signature satisfies threshold requirements, validate the transaction. Otherwise, validation fails.

active permission may grant all other permissions except the owner permission. owner permission grants the same set of permissions, and allows changes to items under owner and active permissions. active permission is required when submitting a transaction.

Permissions can operate with groups. You may add permissions to a group, and add items to that group. This way, the items will enjoy all permissions of the group.

Account System Usage

With smart contracts, there is a simple API to call.

blockchain.requireAuth(id, permission_string)

This will return a boolean value for you to decide whether the operation should continue.

Generally, when using RAM and Tokens, you should first check for active permission of the user, or the smart contract may throw unexpectedly. Pick a unique string for permission_string to minimize the permission.

Normally, you should not be requiring owner permissions, as users shouldn't be asked for owner key unless when modifying owner and active permissions.

There is no need to require a transaction sender, as they always have the active permission.

At user-level, only by supplying the signature do we see users adding permissions. Assume two accounts (and assume 1 for all weights and thresholds of the keys):

User0
├── Groups
│   └── grp0: key3
└── Permissions
    ├── owner: key0
    ├── active: key1
    ├── perm0: key2, grp0
    ├── perm1: User1@active, grp0
    ├── perm2(threshold = 2): key4, key5, grp0
    ├── perm3: key8
    └── perm4(threshold = 2): User@perm3, key9

User1
└── Permissions
    ├── owner: key6
    └── active: key7

RequireAuth form

Parameters	Sig key	Returns	Notes
User0, perm0	key2	true	Permission granted when signature for public key is provided
User0, perm0	key3	true	Permission granted when the group signature is provided
User0, perm0	key1	true	Permissions granted (save for owner permission) when active key is provided
User0, perm1	key7	true	key7 provides User1@active permission, thus granting perm1
User0, owner	key1	false	active does not provide owner permission
User0, active	key0	true	owner grants all permissions
User0, perm2	key4	false	Signatures did not reach threshold
User0, perm2	key4,key5	true	Signatures reached threshold
User0, perm2	key3	true	Permission group does not calculate and check for threshold
User0, perm2	key1	true	active does not check for threshold
User0, perm4	key8	false	Can be implemented when calculating permission group's weight

Creating and Managing Accounts

Account management is based on the contract of auth.iost. The ABI is as follows:

{
  "lang": "javascript",
  "version": "1.0.0",
  "abi": [
    {
      "name": "signUp", // Create account
      "args": ["string", "string", "string"] // Username, ownerKey ID, activeKey ID
    },
    {
      "name": "addPermission", // Add permission
      "args": ["string", "string", "number"] // Username, permission name, threshold
    },
    {
      "name": "dropPermission", // Drop permission
      "args": ["string", "string"] // Username, permission name
    },
    {
      "name": "assignPermission", // Assign permission to an item
      "args": ["string", "string", "string","number"] // Username, permission, public key ID or account_name@permission_name, weight
    },
    {
      "name": "revokePermission",    // Revoke permission
      "args": ["string", "string", "string"] // Username, permission, public key ID or account_name@permission_name
    },
    {
      "name": "addGroup",   // Add permission group
      "args": ["string", "string"] // Username, group name
    },
    {
      "name": "dropGroup",   // Drop group
      "args": ["string", "string"] // Username, group name
    },
    {
      "name": "assignGroup", // Assign item to group
      "args": ["string", "string", "string", "number"] // Username, group name, public key ID or account_name@permission_name, weight
    },
    {
      "name": "revokeGroup",    // Revoke group
      "args": ["string", "string", "string"] // Username, group name, public key ID or account_name@permission_name
    },
    {
      "name": "assignPermissionToGroup", // Assign permission to group
      "args": ["string", "string", "string"] // Username, permission name, group name
    },
    {
      "name": "revokePermissionInGroup", // Revoke permissions from a group
      "args": ["string", "string", "string"] // Username, permission name, group name
    }
  ]
}

Account name are only valid with [a-z0-9_], with a length between 5 and 11. Permission name and group names are only valid with [a-zA-Z0-9_] with a length between 1 and 32.

Every new account need a minimum gas pledgement of 10 IOST, and signUp method will do this pledgement automatically for the new account. So creating a new account needs 10 IOSTs and 0 byte RAM.