syntax = "proto3"; package signrpc; option go_package = "github.com/lightningnetwork/lnd/lnrpc/signrpc"; // Signer is a service that gives access to the signing functionality of the // daemon's wallet. service Signer { /* SignOutputRaw is a method that can be used to generated a signature for a set of inputs/outputs to a transaction. Each request specifies details concerning how the outputs should be signed, which keys they should be signed with, and also any optional tweaks. The return value is a fixed 64-byte signature (the same format as we use on the wire in Lightning). If we are unable to sign using the specified keys, then an error will be returned. */ rpc SignOutputRaw (SignReq) returns (SignResp); /* ComputeInputScript generates a complete InputIndex for the passed transaction with the signature as defined within the passed SignDescriptor. This method should be capable of generating the proper input script for both regular p2wkh output and p2wkh outputs nested within a regular p2sh output. Note that when using this method to sign inputs belonging to the wallet, the only items of the SignDescriptor that need to be populated are pkScript in the TxOut field, the value in that same field, and finally the input index. */ rpc ComputeInputScript (SignReq) returns (InputScriptResp); /* SignMessage signs a message with the key specified in the key locator. The returned signature is fixed-size LN wire format encoded. The main difference to SignMessage in the main RPC is that a specific key is used to sign the message instead of the node identity private key. */ rpc SignMessage (SignMessageReq) returns (SignMessageResp); /* VerifyMessage verifies a signature over a message using the public key provided. The signature must be fixed-size LN wire format encoded. The main difference to VerifyMessage in the main RPC is that the public key used to sign the message does not have to be a node known to the network. */ rpc VerifyMessage (VerifyMessageReq) returns (VerifyMessageResp); /* DeriveSharedKey returns a shared secret key by performing Diffie-Hellman key derivation between the ephemeral public key in the request and the node's key specified in the key_loc parameter (or the node's identity private key if no key locator is specified): P_shared = privKeyNode * ephemeralPubkey The resulting shared public key is serialized in the compressed format and hashed with sha256, resulting in the final key length of 256bit. */ rpc DeriveSharedKey (SharedKeyRequest) returns (SharedKeyResponse); } message KeyLocator { // The family of key being identified. int32 key_family = 1; // The precise index of the key being identified. int32 key_index = 2; } message KeyDescriptor { /* The raw bytes of the key being identified. Either this or the KeyLocator must be specified. */ bytes raw_key_bytes = 1; /* The key locator that identifies which key to use for signing. Either this or the raw bytes of the target key must be specified. */ KeyLocator key_loc = 2; } message TxOut { // The value of the output being spent. int64 value = 1; // The script of the output being spent. bytes pk_script = 2; } message SignDescriptor { /* A descriptor that precisely describes *which* key to use for signing. This may provide the raw public key directly, or require the Signer to re-derive the key according to the populated derivation path. */ KeyDescriptor key_desc = 1; /* A scalar value that will be added to the private key corresponding to the above public key to obtain the private key to be used to sign this input. This value is typically derived via the following computation: * derivedKey = privkey + sha256(perCommitmentPoint || pubKey) mod N */ bytes single_tweak = 2; /* A private key that will be used in combination with its corresponding private key to derive the private key that is to be used to sign the target input. Within the Lightning protocol, this value is typically the commitment secret from a previously revoked commitment transaction. This value is in combination with two hash values, and the original private key to derive the private key to be used when signing. * k = (privKey*sha256(pubKey || tweakPub) + tweakPriv*sha256(tweakPub || pubKey)) mod N */ bytes double_tweak = 3; /* The full script required to properly redeem the output. This field will only be populated if a p2wsh or a p2sh output is being signed. */ bytes witness_script = 4; /* A description of the output being spent. The value and script MUST be provided. */ TxOut output = 5; /* The target sighash type that should be used when generating the final sighash, and signature. */ uint32 sighash = 7; /* The target input within the transaction that should be signed. */ int32 input_index = 8; } message SignReq { // The raw bytes of the transaction to be signed. bytes raw_tx_bytes = 1; // A set of sign descriptors, for each input to be signed. repeated SignDescriptor sign_descs = 2; } message SignResp { /* A set of signatures realized in a fixed 64-byte format ordered in ascending input order. */ repeated bytes raw_sigs = 1; } message InputScript { // The serializes witness stack for the specified input. repeated bytes witness = 1; /* The optional sig script for the specified witness that will only be set if the input specified is a nested p2sh witness program. */ bytes sig_script = 2; } message InputScriptResp { // The set of fully valid input scripts requested. repeated InputScript input_scripts = 1; } message SignMessageReq { // The message to be signed. bytes msg = 1; // The key locator that identifies which key to use for signing. KeyLocator key_loc = 2; } message SignMessageResp { /* The signature for the given message in the fixed-size LN wire format. */ bytes signature = 1; } message VerifyMessageReq { // The message over which the signature is to be verified. bytes msg = 1; /* The fixed-size LN wire encoded signature to be verified over the given message. */ bytes signature = 2; // The public key the signature has to be valid for. bytes pubkey = 3; } message VerifyMessageResp { // Whether the signature was valid over the given message. bool valid = 1; } message SharedKeyRequest { // The ephemeral public key to use for the DH key derivation. bytes ephemeral_pubkey = 1; /* The optional key locator of the local key that should be used. If this parameter is not set then the node's identity private key will be used. */ KeyLocator key_loc = 2; } message SharedKeyResponse { // The shared public key, hashed with sha256. bytes shared_key = 1; }