Class: SignerClient

Pre-configured Protocol intended for communication with Spatium Signer Service

For transport, it uses HTTP(S) + SSE bidirectional transport.
For cache, it uses in-memory storage
For crypto driver, it uses any provided Crypto

As it uses SSETransport internally, one should also keep in mind that the client starts listening as soon as connect is called and does not stop until disconnect is called.

See

Protocol

Hierarchy

Protocol

↳ SignerClient

Implements

Protocol

Constructors

constructor

• new SignerClient(url, auth, crypto, timeout?)

Note

requests are attributed to accountId of an authorization session, thus storing data independently for each authorized user

Example

// Assuming an already initialized Crypto

const auth = new AuthorizationSession('https://cloud.spatium.net/authorization/v1', uuid(randomBytes), ['read', 'secret']);
const signer = new SignerClient('https://cloud.spatium.net/signer/v1', auth, crypto, 10 * 1000);

// Connect to a signer service (with a 10 sec timeout)
await signer.connect(10 * 1000);

// Generate a random secret ID for a new secret (should be done exactly once and kept)
const secretId = uuid(randomBytes);

// Generate both secerts (first on a connected server, and then locally) (should be done once per secret ID)
await signer.generateDistributedSecret(secretId);

// Generate a random session ID for a new synchronization session
const syncSessionId = uuid(randomBytes);

// Perform an ECDSA-over-secp256k1 synchronization procedure for a key with path ```m/44'/0'/0'/0'/0'```
const publicKey = await syncDistributedEcdsaKey(signer, secretId, syncSessionId, 'secp256k1', 0, 0);

// At this point, synchronization data is saved to the storage, so one may access it to get a compound public key
const _publicKey = await getEcdsaPublicKey(signer, syncSessionId);

// Which is obviously the same key that was returned from the synchronization procedure itself
expect(publicKey).toBe(_publicKey);

// Generate a random session ID for a new signing session
const signSessionId = uuid(randomBytes);

// Message to be signed
const message = '7hJ9yN2OdIQo2kJu0arZgw2EKnMX5FGtQ6jlCWuLXCM='

// Get signingToken
const signingToken = await getSigningToken(message)

// Generate an ECDSA signature
const signature = await signEcdsaMessage(signer, secretId, syncSessionId, signSessionId, message, getSigningToken);

// Verify the resulting signature against a compound public key with an external library (elliptic.js here)
expect(new ec('secp256k1').verify(
  Buffer.from(message, 'base64'),
  {
    s: Buffer.from(signature.s, 'base64'),
    r: Buffer.from(signature.r, 'base64'),
    recoveryParam: signature.recovery,
  },
  Buffer.from(publicKey, 'base64'),
)).toBeTruthy();

// Disconnect from signer service
await signer.disconnect();

Parameters

Name	Type	Description
`url`	`string`	signer service endpoint (HTTP(S))
`auth`	`AuthorizationSession`	authorization AuthorizationSession session to use
`crypto`	`Crypto`	any valid Crypto to handle data and computations
`timeout?`	`number`	(optional) per-message request timeout, after which a procedure is dropped

Overrides

Protocol.constructor

Properties

auth

• auth: AuthorizationSession

authorization AuthorizationSession session to use

Methods

connect

▸ connect(timeout?): Promise<void>

Connect and start listening to events

Parameters

Name	Type
`timeout?`	`number`

Returns

Promise<void>

disconnect

▸ disconnect(): Promise<void>

Stop listening for messages and disconnect

Returns

Promise<void>

generateDistributedSecret

▸ generateDistributedSecret(secretId): Promise<void>

Simltaneous genteration of a distributed secret with the same secret ID

This method is not strictly required as one may simply generate secrets with the same ID independently with the help of underlying Crypto Driver however, it's still userful at least for demonstration purposes.

As a result of this operation, new secrets are saved to a permanent storage, accessible by the provided secret ID From this point, one may freely call syncDistributedEcdsaKey and syncDistributedEddsaKey as long as a secret is accessible in the storage.

Example

// Assume an initialized and already connected SignerClient

// Generate a random secret ID for a new secret
const secretId = uuid(randomBytes);

// Generate both secerts (first on a connected server and then locally)
await client.generateDistributedSecret(secretId);

// At this point, the secret is already generated and ready to be used with MPC

Parameters

Name	Type	Description
`secretId`	`string`	ID (UUID) of a secret in question

Returns

Promise<void>