Stellar Bell Upgrade Adds Muxed Contract Addresses and Quantum-Safe Signature Support - Blockonomi
by Brenda Mary · BlockonomiTLDR:
Table of Contents
- TLDR:
- Muxed Contract Addresses for Smart Accounts
- Post-Quantum Signature Support
- Millisecond Ledger Timing and Schedule
- CAP-84 lets one smart contract serve many customers through a new 64-bit ID address format starting with W.
- CAP-87 allows smart contracts to verify ML-DSA signatures, the post-quantum standard NIST finalized in 2024.
- CAP-88 moves ledger close times to a millisecond clock, setting up faster ledgers in future protocol changes.
- The testnet vote is set for November 3, and the mainnet vote follows on November 23 at 1700 UTC.
The Stellar Bell upgrade, also known as Protocol 30, is set to reach mainnet voting on November 23, 2026. The Stellar Development Foundation announced the release on October 20.
The update targets smart accounts for businesses and begins work on quantum-safe signatures and faster ledgers.
It contains three proposed changes: muxed contract addresses, post-quantum signature verification in smart contracts, and millisecond ledger timing. A testnet vote will take place earlier, on November 3.
Muxed Contract Addresses for Smart Accounts
Many exchanges, ramps, and custodial products on Stellar already use muxed accounts. A muxed account attaches an ID to one account. Each customer receives a unique deposit address, while the funds land in a single account.
Smart accounts had no equivalent feature. A smart account is a smart contract instead of a keypair, so it can set its own spending rules. Businesses holding customer balances therefore needed one contract per customer.
CAP-84 addresses this gap in the Stellar Bell upgrade. A contract address can now carry a 64-bit ID, written in a new format that starts with W. Jake Urban, Senior Engineering Manager at the Stellar Development Foundation, described the W as “an upside-down M.”
He said a distinct type lets developers always know which address they handle. Developers must update SDKs and add the W variant to type checks.
Post-Quantum Signature Support
Stellar secures accounts with Ed25519, secp256k1, and secp256r1 elliptic-curve signatures. A large enough quantum computer could break these in theory. No such machine is publicly known, but public keys remain visible on the ledger, and migrations take years.
CAP-87 lets smart contracts verify ML-DSA signatures, a standard NIST finalized in 2024. Verification needs far more computation than Ed25519.
Therefore, Stellar Core performs it directly instead of contract code. This keeps calls cheap and allows testing against official vectors.
Within the Stellar Bell upgrade, this is the first onchain piece of the Quantum Preparedness Plan. Custom account contracts can now require a quantum-safe signature to spend.
Network transaction signatures remain Ed25519 for now. A native post-quantum signer for classic accounts is planned for a later protocol change.
Millisecond Ledger Timing and Schedule
Stellar currently records ledger close times in whole seconds. As a result, the network cannot target intervals shorter than one second. In September, Protocol 28 reduced mainnet close times from about 5.7 seconds to 5 seconds.
CAP-88 moves the ledger to a millisecond clock. This allows future protocol changes to target finer close times. Stellar Core developers are already testing faster closes on experimental branches. The ledger header format also changes, so tools reading ledger data need updated XDR definitions.
SDK users should upgrade before the votes. The previous closeTime field still reports whole seconds. Stellar Core v30.0.0 became available on October 16. The testnet vote occurs on November 3 at 1700 UTC. The mainnet vote follows on November 23 at the same time.