Official address encoding base58check Vs bech32 vs base64

[joyqvq]

discuss after public testnet

[joyqvq]

after some attempts on using bech32 as Address and ObjectID encoding: MystenLabs/sui#5643

there are few challenges that is hard to overcome due to AccountAddress defined in Move:

1. All system object we use 0x5 instead of 0x000000000000000005 for representation, this makes it difficult for an objectID to be represented succinctly in bech32.
2. In move contract, an address type uses AccountAddress in move as underlying, which is represented as hex, example https://github.com/MystenLabs/sui/blob/ea71d821684ccc1bae7034f2229c509c1b5318b8/crates/sui-framework/sources/governance/sui_system.move#L361
   assert!(tx_context::sender(ctx) == @0x0, 0); this will cause a visual discrepancy on how sui uses an address vs what an address looks like onchain.
3. the changes is quite invasive across the board, since we use AccountAddress in rust interchangeablely with SuiAddress and ObjectID (PR attempt: crypto: Use bech32 for SuiAddress encoding sui#5643)

Decision: to keep the address in hex instead of Bech32

[joyqvq]

Another question is whether we want to use 32 or 20 bytes for an hex address? this should be less invasive since there is a flag in Move to do this already. See all changes needed in MystenLabs/sui#6700

[joyqvq]

cc @Jordan-Mysten to add considerations for address 32 bytes frontend

also cc @kchalkias

[benr-ml]

@kchalkias, @joyqvq can we close this one? do you think we will want to change it in the future?

[joyqvq]

MystenLabs/sui#8542 considers 32 bytes hex as final address format for mainnet.