package smartcontract import ( "fmt" "sort" "github.com/nspcc-dev/neo-go/pkg/core/interop/interopnames" "github.com/nspcc-dev/neo-go/pkg/crypto/keys" "github.com/nspcc-dev/neo-go/pkg/io" "github.com/nspcc-dev/neo-go/pkg/vm/emit" "github.com/nspcc-dev/neo-go/pkg/vm/opcode" ) // CreateMultiSigRedeemScript creates an "m out of n" type verification script // where n is the length of publicKeys. func CreateMultiSigRedeemScript(m int, publicKeys keys.PublicKeys) ([]byte, error) { if m < 1 { return nil, fmt.Errorf("param m cannot be smaller or equal to 1 got %d", m) } if m > len(publicKeys) { return nil, fmt.Errorf("length of the signatures (%d) is higher then the number of public keys", m) } if m > 1024 { return nil, fmt.Errorf("public key count %d exceeds maximum of length 1024", len(publicKeys)) } buf := io.NewBufBinWriter() emit.Int(buf.BinWriter, int64(m)) sort.Sort(publicKeys) for _, pubKey := range publicKeys { emit.Bytes(buf.BinWriter, pubKey.Bytes()) } emit.Int(buf.BinWriter, int64(len(publicKeys))) emit.Opcodes(buf.BinWriter, opcode.PUSHNULL) emit.Syscall(buf.BinWriter, interopnames.NeoCryptoCheckMultisigWithECDsaSecp256r1) return buf.Bytes(), nil } // CreateDefaultMultiSigRedeemScript creates an "m out of n" type verification script // using publicKeys length with the default BFT assumptions of (n - (n-1)/3) for m. func CreateDefaultMultiSigRedeemScript(publicKeys keys.PublicKeys) ([]byte, error) { n := len(publicKeys) m := GetDefaultHonestNodeCount(n) return CreateMultiSigRedeemScript(m, publicKeys) } // CreateMajorityMultiSigRedeemScript creates an "m out of n" type verification script // using publicKeys length with m set to majority. func CreateMajorityMultiSigRedeemScript(publicKeys keys.PublicKeys) ([]byte, error) { n := len(publicKeys) m := n - (n-1)/2 return CreateMultiSigRedeemScript(m, publicKeys) } // GetDefaultHonestNodeCount returns minimum number of honest nodes // required for network of size n. func GetDefaultHonestNodeCount(n int) int { return n - (n-1)/3 }