BSIP: 0029
    Title: Asset issue change to require owner authority
    Authors: Fabian Schuh <Fabian.Schuh@blockchainprojectsbv.com>
    Status: Accepted
    Type: Protocol
    Created: 2018-01-28
    Discussion: https://github.com/bitshares/bitshares-core/issues/199
    Worker: 1.14.81

# Abstract

With the current design, the issuer of an asset can be changed with the
*active authority* alone. However, this authority is also required for
issuing new units of an asset/token. If this process wants to be
automated, an active key needs to be stored on an internet-connected
device. If compromised, an attacker can easily move the asset under his
control with no way to back.

This proposal comes with two changes to the protocol:

1. The current behavior of changing an assets' parameters will no longer
   allow to change the issuer.
2. A new operation is introduced that allows to change the issuer of an
   asset but requires the owner authority of the issuer to sign that
   transaction.

# Motivation

Improve asset security.

# Rational

Assets should not be at risk while automating issuing of new units.

# Specifications

## Current Design and Implementation

Currently, any asset can be updated with `asset_update_operation`. This
operation contains an optional `new_issuer` that changes the issuer of
the asset.

## Proposed Changes

# `asset_update_operation`

The existing `asset_update_operation` will be modified in such that it
no longer allows the user of `new_issuer` after a hard fork.

# `asset_update_issuer_operation`

A new operation is added with the following construction

```

   struct asset_update_issuer_operation : public base_operation
   {
      struct fee_parameters_type {uint64_t fee = 20 * GRAPHENE_BLOCKCHAIN_PRECISION; };

      asset           fee;
      account_id_type issuer;
      asset_id_type   asset_to_update;
      account_id_type new_issuer;
      extensions_type extensions;

      account_id_type fee_payer()const { return issuer; }
      void            validate()const;

      void get_required_owner_authorities( flat_set<account_id_type>& a )const
      { a.insert( issuer ); }

      void get_required_active_authorities( flat_set<account_id_type>& a )const
      {  }

   };
```

This new operation merely allows to change the issuer of an asset and
requires the owner authority (of the issuer account) to sign the
transaction.

# Summary for Shareholders

We here propose the addition of a new operation that improves security
of assets with respect to updating the issuer. This closes a long
existing problem that makes running automated issuing of units a
security issue since an attacker that obtains the keys can obtain full
control of an asset indefinitely. This proposal changes this behavior
and requires the owner to sign such change of issuer.

# Copyright

This document is placed in the public domain.

# Sponsoring

This worker proposal is proudly presented and sponsored by [Blockchain Projects BV](http://blockchainprojectsbv.com).