Stacks Namespace - SIWx

Author Léo Pradel @pradel
Discussions-To https://forum.stacks.org/t/caip-2-and-caip-10-stacks-specification/13290
Status Draft
Type Standard
Created 2023-01-08
Requires CAIP-122, CAIP-2, CAIP-10

Table of Contents

CAIP-122

For context, see the CAIP-122 specification.

Rationale

This specification provides the signing algorithm to use, the type of the signing algorithm to identify it, and a method for signature creation and verification as required by CAIP-122.

Specification

Signing Algorithm

Stacks uses the ECDSA secp256k1 signing algorithm for signing and verifying messages. The message is hashed with SHA256 before being used as an input for signing.

Signature Type

We propose using the signature type stacks:secp256k1 to refer to the chain and algorithm used uniquely.

Signature Creation

The abstract data model defined by CAIP-122 must be converted into a string representation in an unambigious format, and then the string converted to a byte array to be signed over.

We propose the following string format, inspired by EIP-4361.

${domain} wants you to sign in with your Stacks account:
${address}
${statement}
URI: ${uri}
Version: ${version}
Chain ID: ${chain-id}
Nonce: ${nonce}
Issued At: ${timestamp}
Expiration Time: ${expiration-time}
Not Before: ${not-before}
Request ID: ${request-id}
Resources:
- ${resources[0]}
- ${resources[1]}
...
- ${resources[n]}

Signature Verification

As in other secp256k1 systems, the public key from which an address is derived can be recovered by smart contracts or elsewhere from a signature and the signing address, via the Stacks equivalent of the ECRecover pattern. With the signature and public key, the message can be verified using the same algorithm as for signature creation. The message needs to be hashed with SHA256 before being used as an input for verification.

References

Citation

Please cite this document as:

Léo Pradel @pradel, "namespaces/stacks-caip122: Stacks Namespace - SIWx [DRAFT]," Chain Agnostic Namespaces, stacks-caip122, January 2023 / . [Online serial]. Available: https://github.com/ChainAgnostic/namespaces/stacks-caip122.md