Nutshell 0.20.3

Nutshell 0.20.3 adds P2BK and Spark support, plus mint UX and reliability improvements.

Notable Changes

Mint

• NUT-28 P2BK (Pay-to-Blinded-Key): lock ecash to a receiver without revealing their pubkey to the mint (silent payments / payment unlinkability).
• Spark L2 wallet backend for Lightning payments via Spark.
• Interactive HTML landing page at the mint root route (/) showing mint info, limits, contacts, and supported NUTs.
• method field on mint/melt quote responses (spec alignment).
• Management RPC: GetKeyset / GetKeysets with issued liabilities and fees; matching mint-cli subcommands.
• NUT-11 sig_all message aggregation extended to match the latest spec.
• NUT-20/29 signatures aligned with the current spec (incl. test vectors).
• Async melt race fixed: durable PENDING is committed before the HTTP response so clients don’t see a false terminal UNPAID.
• Melt change cleanup: orphan blank outputs are deleted on early-return paths (fixes restore collisions).
• Batch mint issued_time and legacy base64url keyset ID handling fixed.
• Docker Compose Redis bound to localhost only.

Wallet

• NUT-28 P2BK support for creating and receiving P2BK-locked tokens.
• cashu send --timelock/-t: per-send locktime override (matches cashu lock p2pk).
• Missing mint keysets are marked deleted instead of leaving stale active state.

What's Changed

• Mark Keysets as Deleted. by @KvngMikey in #797
• feat(mint): add method field to quote responses. by @KvngMikey in #1055
• Remove paid field in MeltQuote by @KvngMikey in #1024
• feat(mint): add keyset and keysets endpoints to management RPC with issued liabilities by @a1denvalu3 in #1078
• fix(docker): restrict redis access to localhost in compose by @a1denvalu3 in #1079
• extend and refactor nut11 sig_all message aggregation by @callebtc in #811
• feat(crypto): align NUT-20/29 signatures with spec and add test vectors by @a1denvalu3 in #1057
• feat(mint): add interactive html landing page at root route by @a1denvalu3 in #1077
• feat: support NUT-28 P2BK by @KvngMikey in #950
• feat(mint): Add Spark L2 wallet backend by @a1denvalu3 in #1019
• fix(mint): delete orphan blank outputs on melt change early-return by @gorrdy in #1016
• fix: await ledger.melt() call in test_melt_quote_reuse_same_outputs by @vicjuma in #1080
• chore: retire legacy curve mapping by @a1denvalu3 in #1082
• fix: complete remaining Pydantic v1 to v2 migration by @vicjuma in #1084
• fix(mint): commit PENDING before async melt response by @callebtc in #1087
• fix: handle batch mint times and base64url keysets by @a1denvalu3 in #1091
• refactor(mint): recalculate DLEQs on restore by @a1denvalu3 in #1085
• feat(cli): add --timelock/-t option to send command by @KvngMikey in #1090
• chore(release): bump version to 0.20.3 by @callebtc in #1093

New Contributors

• @vicjuma made their first contribution in #1080

Full Changelog: 0.20.2...0.20.3