Quantus Namespace - Addresses

CAIP-10

For context, see the CAIP-10 specification.

Rationale

A Quantus account is identified on-chain by a 32-byte account ID. For accounts controlled by a key, the account ID is the Poseidon hash of the ML-DSA public key. Both ML-DSA-87 and ML-DSA-65 keys are supported, and the account ID does not reveal which was used. The public key itself is 2592 bytes for ML-DSA-87 or 1952 bytes for ML-DSA-65 and is never used as an address; it is only revealed inside a signed transaction. Other account IDs, such as multisig and pallet-derived accounts, are 32-byte values with no corresponding key.

Account IDs are presented to users in SS58 encoding with the network prefix 189, which is registered to Quantus in the SS58 registry. Every Quantus network uses the same prefix, so a given account ID has the same address string on mainnet and on Planck. The CAIP-2 chain ID is what distinguishes the two.

Syntax

An SS58 address with prefix 189 is the base58btc encoding of:

1. the two prefix bytes 0x6f 0x40 (the SS58 encoding of 189),
2. the 32-byte account ID,
3. a 2-byte checksum: the first two bytes of blake2b-512("SS58PRE" || prefix bytes || account ID).

The result is always 49 characters long and always starts with qz. The account_address segment of a Quantus CAIP-10 is that string, unchanged.

account_id:        chain_id + ":" + account_address
chain_id:          "quantus:" + [a-z0-9]{3,32}
account_address:   "qz" + [1-9A-HJ-NP-Za-km-z]{47}

A regular expression for validating the syntax, without verifying the checksum, is:

^quantus:[a-z0-9]{3,32}:qz[1-9A-HJ-NP-Za-km-z]{47}$

Full validation decodes the address, checks that the prefix bytes are 0x6f40 and recomputes the checksum. Any SS58 library that accepts a numeric prefix can do this with prefix 189.

Backwards Compatibility

Not applicable.

Test Cases

This is a list of manually composed examples. Each account ID is shown in hex followed by its address on both networks:

# Account ID 0xbe13a189f99c44a959e26694ffe5e4ba223092f3edbe8259c1d45ad08edb403d
quantus:mainnet:qzokTZkdWXxMgSXyF86ECHxG8o8yRX5ibrX2Uw8YmqkHRdj1V
quantus:planck:qzokTZkdWXxMgSXyF86ECHxG8o8yRX5ibrX2Uw8YmqkHRdj1V

# Account ID 0x586c2cc8b99325a0455f20485fce964f040670a810ee4639e5f6ce9b85215c66
quantus:mainnet:qzmTAz3UUw1WGUuVh8nbFmPwcftomduwy6twq6NDR6y9qqtEs
quantus:planck:qzmTAz3UUw1WGUuVh8nbFmPwcftomduwy6twq6NDR6y9qqtEs

# Account ID 0x3179fa8be95211111e314411647708c64227ef4bdcb26ea1a5026a4542363a23
quantus:mainnet:qzka7DZXAT7GnzgXQfxiSwrPKRWgW6m6G89QRsQiLThThZ6Cw
quantus:planck:qzka7DZXAT7GnzgXQfxiSwrPKRWgW6m6G89QRsQiLThThZ6Cw

References

• Quantus documentation - developer documentation for Quantus Network
• Post-quantum cryptography in Quantus - how ML-DSA keys and Poseidon account derivation work
• SS58 - the address encoding
• SS58 registry - the registry in which prefix 189 is assigned to Quantus
• FIPS 204 - the ML-DSA signature standard

Copyright

Copyright and related rights waived via CC0.

Citation

Please cite this document as:

["Nikolaus Heger, "namespaces/quantus-caip10: Quantus Namespace - Addresses [DRAFT]," Chain Agnostic Namespaces, quantus-caip10, September 2026 / . [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/quantus-caip10.md