HIP-394: Add Expected Decimal Information to TokenMint, TokenBurn, and TokenWipeAccount
| Author | Ryan Leckey |
|---|---|
| Discussions-To | https://github.com/hashgraph/hedera-improvement-proposal/discussions/393 |
| Status | Accepted ⓘ |
| Needs Council Approval | Yes ⓘ |
| Review period ends ⓘ | Tue, 05 Apr 2022 07:00:00 +0000 |
| Type | Standards Track ⓘ |
| Category | Service ⓘ |
| Created | 2022-03-08 |
| Updated | 2023-01-20 |
Table of Contents
Abstract
This specification proposes a way to add expected decimal information for tokens to
the TokenMint, TokenBurn, and TokenWipeAccount transaction.
Motivation
The motivation for this HIP is identical to the motivation for HIP-31. These additional transactions also need the decimal information for use in a hardware wallet.
Rationale
The below change to token transfer protobuf messages is formulated to incur a minimal operational cost to the network while providing enough information to address hardware wallet security concerns.
Specification
message TokenMintTransactionBody {
// [...]
/**
* If present, the number of decimals this fungible token type is expected to have. The transfer
* will fail with UNEXPECTED_TOKEN_DECIMALS if the actual decimals differ.
*/
UInt32Value expected_decimals = 4;
}
message TokenBurnTransactionBody {
// [...]
/**
* If present, the number of decimals this fungible token type is expected to have. The transfer
* will fail with UNEXPECTED_TOKEN_DECIMALS if the actual decimals differ.
*/
UInt32Value expected_decimals = 4;
}
message TokenWipeAccountTransactionBody {
// [...]
/**
* If present, the number of decimals this fungible token type is expected to have. The transfer
* will fail with UNEXPECTED_TOKEN_DECIMALS if the actual decimals differ.
*/
UInt32Value expected_decimals = 5;
}
Backwards Compatibility
It shouldn’t break existing messages, and will provide needed information for some applications going forward.
Security Implications
A Ledger hardware wallet user would be able to trust that the fractional display of a token transfer is coming from an on wire message that they are signing with their private key.
References
HIP-31: https://hips.hedera.com/hip/hip-31
Copyright/license
This document is licensed under the Apache License, Version 2.0 – see LICENSE or (https://www.apache.org/licenses/LICENSE-2.0)
Citation
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