Changelog

0.2.0 — 2026-07-01

Hedera.Client.create_contract/2 and call_contract/3 (Hedera.Transaction.contract_create/1 / contract_call/1), with Hedera.ContractId and contract_id on the receipt. contract_create accepts inline :bytecode (EVM init) or a bytecode :file, plus :gas, :admin_key, :constructor_parameters, :initial_balance. Validated live: deploy inline bytecode → SUCCESS + contract id → call the contract → SUCCESS (contractCreateInstance = 8, contractCall = 7; return values live in the record, not the receipt — reading them is a follow-up).

Vendored the subset of the HAPI protobufs hedera_ex uses (priv/protos/hedera_min.proto, canonical field numbers) and generate Elixir modules under Hedera.Pb.* via protoc + protoc-gen-elixir (priv/protos/generate.sh). Adds the protobuf dependency.
Hedera.Transaction now builds and encodes every transaction from generated structs, and Hedera.Receipt decodes via the generated TransactionReceipt — hand-rolled field-by-field encoding is gone from the transaction/receipt layer. (The generated encoder is proto3-canonical: it omits zero-valued fields and packs repeated scalars, e.g. NFT serialNumbers.)
An equivalence test pins the generated modules as wire-compatible with the original hand-rolled encoder in both directions (submit-message bytes, generated↔Hedera.Proto decode, ZigZag sint64, receipts). The full transaction suite — HCS / Crypto / HTS / NFT / File / Schedule — was re-validated live on testnet after the migration (all SUCCESS). (Hedera.Proto remains for the small gRPC query/response framing.)

Hedera.Client.create_file/2, append_file/4, update_file/3, delete_file/2 (Hedera.Transaction.file_create/1 etc.), with Hedera.FileId and file_id on the receipt. Files carry a KeyList (defaults to the operator's key → mutable). Validated live: create → append → update → delete, all SUCCESS.

Hedera.Client.create_schedule/2 (a scheduled HBAR/token transfer) and sign_schedule/3 (Hedera.Transaction.schedule_create/1 / schedule_sign/1), with Hedera.ScheduleId and schedule_id on the receipt. The scheduled transaction is a SchedulableTransactionBody — note its data-oneof numbering differs from TransactionBody (cryptoTransfer = 9). Validated live: create a transfer pending on a second signer → sign_schedule → it executes.

NFTs — token_create with token_type: :nft (NON_FUNGIBLE_UNIQUE); token_mint with :metadata (a list of binaries); mint receipts now expose serial_numbers (packed or unpacked). NFT transfers via Hedera.Client.transfer_nft/4 (CryptoTransfer nftTransfers).
Management — freeze_token / unfreeze_token, grant_kyc / revoke_kyc, wipe_token (fungible amount or NFT serials), pause_token / unpause_token. token_create now accepts :kyc_key, :freeze_key, :wipe_key, :pause_key.
Validated live (testnet): create NFT → mint (serials [1,2]) → pause/unpause; then associate → grantKyc → NFT transfer → freeze/unfreeze → wipe — every step a SUCCESS receipt, confirming the tokenFreeze(31)/tokenUnfreeze(32)/grantKyc(33)/revokeKyc(34)/tokenWipe(39)/ tokenPause(46)/tokenUnpause(47) field numbers and the nftTransfers encoding.

The cryptographic and encoding foundation, fully unit-tested offline:

Keccak-256 — pure Elixir (Hedera/Ethereum padding), verified against known vectors.
Keys — Hedera.PrivateKey / Hedera.PublicKey for Ed25519 and ECDSA secp256k1, with Hedera's signing conventions (Keccak-256 prehash + canonical low-S r‖s for ECDSA), 33-byte compressed public keys, sign/verify, hex round-trip.
Identifiers — AccountId, TopicId, Timestamp (parse / format / protobuf).
Protobuf — minimal proto3 wire encoder (Hedera.Proto).

Transactions — Hedera.Transaction encodes and signs TransactionBody → SignedTransaction → Transaction for consensusSubmitMessage and consensusCreateTopic.
gRPC — Hedera.Grpc (unary over HTTP/2 h2c via Mint), Hedera.Network (testnet/mainnet nodes), Hedera.Client (submit_message/3, create_topic/2).
Validated live: a natively-built, natively-signed HCS message submit is accepted by a Hedera testnet node (pre-check OK), confirming protobuf field numbers and signing end-to-end. (mix test --include network.)

Receipts — Hedera.Client.transaction_receipt/3 polls the free gRPC getTransactionReceipts; Hedera.Receipt parses status, topic sequence number and running hash. Verified live (submit → SUCCESS receipt with a sequence number).
Mirror node — Hedera.MirrorNode REST reads (topic messages, transactions); adds jason.

Address book + retry — Hedera.Network.testnet_nodes/0 lists multiple consensus nodes; Hedera.Client rebuilds + re-signs per target node and retries the next node on transient (BUSY) pre-checks or transport errors.

Transfers — Hedera.Transaction.crypto_transfer/1 and Hedera.Client.transfer_hbar/3 build and sign a cryptoTransfer of HBAR between accounts. Amounts are encoded as protobuf sint64 (ZigZag, via Hedera.Proto.sint64_field/2); debits are negative, credits positive, and must net to zero.
Validated live: a natively-built transfer is accepted by a testnet node (pre-check OK) and reaches a SUCCESS receipt, confirming the cryptoTransfer field numbers and the TransferList / AccountAmount (sint64) encoding end-to-end.

Tokens — Hedera.Transaction gains token_create/1, token_mint/1, token_burn/1 and token_associate/1; crypto_transfer/1 now also carries :token_transfers. Hedera.Client gains create_token/2, mint_token/4, burn_token/4, associate_token/4, transfer_token/4. New Hedera.TokenId; Hedera.PublicKey.to_key_proto/1 encodes a Key message (Ed25519 in field 2, ECDSA secp256k1 in field 7); Hedera.Receipt now parses token_id and new_total_supply.
Multi-signature — transaction building accepts :signers (extra keys beyond the operator); the signature map carries one SignaturePair per distinct key, so e.g. a token association can be signed by both the fee-paying operator and the account being associated.
Validated live (full lifecycle on testnet): create a fungible token → mint supply (receipt token_id + new_total_supply) → associate a second account (multi-sig: operator ECDSA + account Ed25519) → transfer tokens to it — every step reaches a SUCCESS receipt. This confirms the tokenCreation (29) / tokenMint (37) / tokenAssociate (40) field numbers, the Key encoding, and TokenTransferList end-to-end.

Next: NFT mint/metadata, token freeze/kyc/wipe, protoc-generated messages, hex.pm release.