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PIP-8: Defining address type based on the address usage

Authors Kayhan Alizadeh []
B00f (@b00f )
Discussion View Discussion PIP-8
Created 2023-09-17


This proposal suggests defining the address type based on their usage, not the cryptographic algorithm. With this approach, addresses can communicate their intended usage.

PIP-8 - address format


Addresses in Pactus are defined as <Type> + <20 Data>. Currently, the type only indicates the cryptographic algorithm of the corresponding public key. It is defined as 1 for the BLS signature schema. However, there are some problems with this approach:

  1. The address can be misused. For example, a user might use an account address as a validator address in a Bond transaction (An issue regarding this problem is reported here).

  2. The address doesn’t indicate its usage. This makes it challenging for both humans and machines to identify the purpose of each address, whether it belongs to an Account or Validator. This is particularly troublesome in applications like block explorers.


We propose to define address types as follows:

0: Treasury address
1: Validator address
2: BLS-Account address

For the treasury address, the data is a string of zeros in 21-byte length: 000000000000000000000000000000000000000000. In both Validator address and BLS-Account address, the data is the hash of the corresponding public key.


Examples of validator address:

  • pc1p97d72u2nqfwq3rv3kfuy0xaeuvkk6ye5cl2vyp
  • pc1ppjedvfsd02x74j83ceu0kju37652u253z9cnh6
  • pc1pnetupg0ewf2r0l8hx9052d3g4zf8dpzlf9qgps

Examples of BLS-account address:

  • pc1zwqxz2wmz5upuvxzj3kpgfq3k2are4s3ctqxtxy
  • pc1zhjk4pujm770elt30ud2d868czg9kth3e3nefnl
  • pc1zzya8am0h0y0nu6msxz5j5pt9tsqsdvgzs5r89v

Note that validator addresses start with pc1p, and BLS account addresses start with pc1z.

Address derivation path

Currently, the wallet derivation path in Pactus is similar to EIP-2334. To align with this proposal, we suggest changing the derivation path to:

m / purpose' / coin_type' / address_type' / address_index

The apostrophe in the path indicates that hardened derivation is used.

Each level is defined as follows:


The purpose is set to 12381, representing the BLS12-381 curve. This indicates the use of the BLS subtree for the derivation path.

Hardened derivation is used at this level.

Coin type

The coin type is set to 21888, which matches the PAC coin type registered at SLIP-0044.

Hardened derivation is used at this level.

Address type

The address type is same as the type of address, setting 1 for validators and 2 for accounts. The value 0 is reserved and is not used.

Hardened derivation is used at this level.

Address Index

Addresses start from index 0 and increase sequentially. This number is similar to the child index in BIP32 derivation.

Non-Hardened derivation is used at this level.



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