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https://github.com/luxfi/mpc.git
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zeekayandHanzo Dev
c84366bc62
Deploys and contract calls on the Lux C-Chain signed from a plaintext mnemonic or a k8s-held private key. Route them through the MPC instead: pkg/evm derives the account from the keygen secp256k1 pubkey, sends the transaction digest to the existing CGGMP21 /v1/mpc/sign oracle, and assembles r,s,v — the key is never reconstructed in one place. SignTx recovers the sender from the signature it just applied and refuses if it is not the signer's own account, so a wrong recovery id is caught before broadcast rather than after. `mpc evm address|recover|sign|tx` drives it from the CLI. The /v1/mpc/sign HTTP responses now also return v, matching the KMS and ZAP paths. Co-authored-by: Hanzo Dev <[email protected]>
82 lines
3.0 KiB
Go
82 lines
3.0 KiB
Go
package evm
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import (
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"context"
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"fmt"
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"math/big"
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"github.com/luxfi/geth/common"
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"github.com/luxfi/geth/core/types"
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)
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// SignTx assembles a broadcast-ready signed transaction. It computes the digest
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// the transaction is signed over for chainID, asks the signer for a threshold
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// signature over that digest, applies it, and — before returning — recovers the
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// sender and checks it is the signer's own account. A wrong recovery id would
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// bind the transaction to a different account and spend from nobody; that is
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// caught here and refused, never broadcast.
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//
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// chainID is the EVM chain id (Lux mainnet is 96369). The digest and the applied
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// signature both follow the transaction's own type — legacy, EIP-155, or typed —
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// because the signer returned by LatestSignerForChainID handles all of them.
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func SignTx(ctx context.Context, s Signer, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
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if chainID == nil || chainID.Sign() <= 0 {
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return nil, fmt.Errorf("evm: chain id must be positive, got %v", chainID)
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}
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signer := types.LatestSignerForChainID(chainID)
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digest := signer.Hash(tx)
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sig, err := s.Sign(ctx, digest[:])
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if err != nil {
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return nil, err
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}
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signed, err := tx.WithSignature(signer, sig.Bytes())
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if err != nil {
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return nil, fmt.Errorf("evm: apply signature: %w", err)
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}
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from, err := types.Sender(signer, signed)
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if err != nil {
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return nil, fmt.Errorf("evm: recover sender: %w", err)
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}
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if from != s.Account() {
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return nil, fmt.Errorf("evm: signature binds tx to %s, want %s", from, s.Account())
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}
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return signed, nil
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}
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// Digest returns the 32-byte value a transaction is signed over for chainID —
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// the input to hand an MPC signing round when a caller wants to sign and
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// assemble in two separate steps (build the digest here, sign it through the
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// quorum, then Apply). Signing and assembling in one call is SignTx.
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func Digest(tx *types.Transaction, chainID *big.Int) ([]byte, error) {
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if chainID == nil || chainID.Sign() <= 0 {
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return nil, fmt.Errorf("evm: chain id must be positive, got %v", chainID)
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}
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h := types.LatestSignerForChainID(chainID).Hash(tx)
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return h[:], nil
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}
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// Apply attaches a signature obtained out of band (from an MPC signing round
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// over Digest(tx)) and verifies it binds the transaction to want. It is the
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// second half of the two-step path whose first half is Digest.
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func Apply(tx *types.Transaction, chainID *big.Int, sig Signature, want common.Address) (*types.Transaction, error) {
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if chainID == nil || chainID.Sign() <= 0 {
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return nil, fmt.Errorf("evm: chain id must be positive, got %v", chainID)
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}
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signer := types.LatestSignerForChainID(chainID)
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signed, err := tx.WithSignature(signer, sig.Bytes())
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if err != nil {
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return nil, fmt.Errorf("evm: apply signature: %w", err)
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}
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from, err := types.Sender(signer, signed)
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if err != nil {
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return nil, fmt.Errorf("evm: recover sender: %w", err)
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}
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if from != want {
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return nil, fmt.Errorf("evm: signature binds tx to %s, want %s", from, want)
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}
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return signed, nil
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}
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