Onchain.Signer.Secp256k1 (onchain v0.16.0)

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Signer backend that signs with a local secp256k1 private key.

Implements Onchain.Signer.Backend — its config is the raw private-key binary. The behaviour's Onchain.Signer.Backend.sign_payload/2 signs the 32-byte digest it is handed directly; sign/2 is a convenience wrapper that keccaks a raw message first.

Uses the precompiled RustCrypto k256 backend. Private keys remain in BEAM memory; use Onchain.Signer.CloudKMS when keys must stay in an HSM.

Summary

Functions

get_address(private_key)

Get the Ethereum address associated with the given private key.

public_key(private_key)

Get the uncompressed secp256k1 public key for the given private key.

sign(message, private_key)

Signs a raw message, keccak-digesting it first.

sign_digest(message_hash, private_key)

Deprecated alias for sign_payload/2; signs an already-digested message.

sign_payload(arg, private_key)

Signs the 32-byte digest it is handed directly — the pure-payload contract.

Functions

get_address(private_key)

@spec get_address(binary()) :: {:ok, binary()} | {:error, atom()}

Get the Ethereum address associated with the given private key.

Examples

iex> priv_key = "800509fa3e80882ad0be77c27505bdc91380f800d51ed80897d22f9fcc75f4bf" |> Base.decode16!(case: :mixed)
iex> {:ok, address} = Onchain.Signer.Secp256k1.get_address(priv_key)
iex> Onchain.Hex.to_address(address)
"0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7"

public_key(private_key)

@spec public_key(binary()) :: {:ok, binary()} | {:error, atom()}

Get the uncompressed secp256k1 public key for the given private key.

Examples

iex> priv_key = "800509fa3e80882ad0be77c27505bdc91380f800d51ed80897d22f9fcc75f4bf" |> Base.decode16!(case: :mixed)
iex> {:ok, pub} = Onchain.Signer.Secp256k1.public_key(priv_key)
iex> Onchain.Hex.to_address(Onchain.Address.from_public_key(pub))
"0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7"

sign(message, private_key)

@spec sign(String.t(), binary()) :: {:ok, Onchain.Signature.t()} | {:error, atom()}

Signs a raw message, keccak-digesting it first.

Back-compat convenience over sign_payload/2 for EIP-191-style raw-message signing; for typed data (EIP-712, Hyperliquid) the caller should compute the digest and call sign_payload/2 directly.

Examples

iex> use Onchain.Hex
iex> priv_key = ~h[0x800509fa3e80882ad0be77c27505bdc91380f800d51ed80897d22f9fcc75f4bf]
iex> {:ok, sig} = Onchain.Signer.Secp256k1.sign("test", priv_key)
iex> {:ok, recid} = Onchain.Recover.find_recid("test", sig, ~h[0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7])
iex> Onchain.Recover.recover_eth("test", %{sig|recid: recid}) |> Onchain.Hex.to_address()
"0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7"

sign_digest(message_hash, private_key)

@spec sign_digest(String.t(), binary()) ::
  {:ok, Onchain.Signature.t()} | {:error, atom()}

Deprecated alias for sign_payload/2; signs an already-digested message.

sign_payload(arg, private_key)

@spec sign_payload(<<_::256>>, binary()) ::
  {:ok, Onchain.Signature.t()} | {:error, atom()}

Signs the 32-byte digest it is handed directly — the pure-payload contract.

This performs no hashing: the caller (Onchain.Signer) owns digest computation, so the same backend serves plain Eth tx, EIP-712, and Hyperliquid.

Examples

iex> use Onchain.Hex
iex> priv_key = ~h[0x800509fa3e80882ad0be77c27505bdc91380f800d51ed80897d22f9fcc75f4bf]
iex> message_hash = ~h[0x9c22ff5f21f0b81b113e63f7db6da94fedef11b2119b4088b89664fb9a3cb658]
iex> {:ok, sig} = Onchain.Signer.Secp256k1.sign_payload(message_hash, priv_key)
iex> {:ok, recid} = Onchain.Recover.find_recid("test", sig, ~h[0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7])
iex> Onchain.Recover.recover_eth("test", %{sig|recid: recid}) |> Onchain.Hex.to_address()
"0x63Cc7c25e0cdb121aBb0fE477a6b9901889F99A7"