Both QRL chains write addresses starting with a capital Q. That shared prefix is convenient branding, but it hides an important fact: the two chains use different address formats, and the way to tell them apart is length, not prefix.
The two formats
| QRL Legacy | QRL 2.0 | |
|---|---|---|
| Total length | 79 characters | 41 characters (testnet v2) or 129 characters (testnet V3, mainnet) |
| Prefix | Q | Q |
| Hex characters | 78 | 40 or 128 |
| Binary size | 39 bytes | 20 or 64 bytes |
| Derived from | XMSS public key | ML-DSA-87 public key |
A glance at the length is all you need: 79 = Legacy, 41 or 129 = QRL 2.0.
How a QRL Legacy address is built (39 bytes)
A Legacy address encodes 39 bytes, which become 78 hex characters after the Q:
- 3-byte descriptor — records the signature scheme and its parameters (for example, the hash function and tree height).
- 32-byte hash — a SHA-256 hash of the extended public key.
- 4-byte checksum — the leading bytes of a second SHA-256, used to detect typos before a transaction is sent.
This structure comes straight from XMSS: because the address commits to the signature parameters in its descriptor, the chain knows how to verify signatures against it.
How a QRL 2.0 address is built (20 or 64 bytes)
QRL 2.0 is EVM-compatible. On testnet v2 its addresses are the same 20-byte size as Ethereum's — 40 hex characters after the Q, 41 characters in total. From testnet V3, and on mainnet, addresses are 64 bytes — 128 hex characters after the Q, 129 characters in total — and the virtual machine works with 64-byte words to match. Either way the address is derived from the ML-DSA-87 public key with a hash rather than the Keccak hash Ethereum uses (SHAKE-256 for the 20-byte format). The visible difference from Ethereum is the prefix: QRL 2.0 writes Q… where Ethereum writes 0x….
Nodes and wallets print 64-byte addresses with a mix of upper- and lower-case letters. That casing is a checksum (QIP-55, similar to Ethereum's EIP-55) that catches typos; it does not change the address, and the explorer accepts either case.
Why you can't convert one to the other
A common misconception is that a holder's Legacy address and their QRL 2.0 address must be related. They are not. The two are derived from different keys (an XMSS key vs an ML-DSA-87 key) using different schemes. There is no function that turns one into the other.
When QRL Legacy value moves to QRL 2.0, the link between an old and a new address is a claim recorded during the process — not something anyone can compute from the addresses themselves. This explorer treats any such link as a claim, never as a derivable fact. The mechanics are covered in the QRL → QRL 2.0 migration.
What this means on the explorer
- Paste either format into the search bar and the explorer routes it to the right chain automatically, using the length to decide.
- A 79-character result is always Legacy; a 41- or 129-character result is always QRL 2.0.
- The same person may hold addresses on both chains, but the explorer never assumes two addresses are "the same wallet" unless a migration claim says so.
Where to go next
- XMSS explained and ML-DSA-87 explained — the schemes behind each format.
- Reading a block explorer — putting addresses, blocks and transactions together.