feat: add simple runnable sample (#94)

Author: tplooker

README.md

@@ -40,6 +40,8 @@ yarn add @mattrglobal/node-bbs-signatures
 
 ## Usage
 
+See the [sample](./sample) directory for a runnable demo.
+
 The following is a short sample on how to use the API
 
 ```typescript

sample/README.md

@@ -0,0 +1,10 @@
+# node-bbs-signatures-sample
+
+A simple runnable sample demoing how to use the API.
+
+Run the following and observe the console output
+
+```
+yarn install --frozen-lockfile
+yarn demo
+```

sample/package.json

@@ -0,0 +1,21 @@
+{
+  "name": "node-bbs-signatures-sample",
+  "version": "1.0.0",
+  "description": "A sample for using node-bbs-signatures",
+  "main": "lib/index.js",
+  "repository": "https://github.com/mattrglobal/node-bbs-signatures",
+  "author": "Mattr Limited",
+  "license": "Apache 2.0",
+  "private": false,
+  "scripts": {
+    "demo": "ts-node ./src/index.ts"
+  },
+  "devDependencies": {
+    "@types/node": "12.7.2",
+    "ts-node": "8.4.1",
+    "typescript": "3.7.5"
+  },
+  "dependencies": {
+    "@mattrglobal/node-bbs-signatures": "0.5.0"
+  }
+}

sample/src/index.ts

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2020 - MATTR Limited
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {
+  generateBls12381KeyPair,
+  blsSign,
+  blsVerify,
+  blsCreateProof,
+  blsVerifyProof,
+} from "@mattrglobal/node-bbs-signatures";
+
+const main = (): void => {
+  //Generate a new key pair
+  const keyPair = generateBls12381KeyPair();
+
+  console.log("Key pair generated");
+  console.log(`Public key base64 = ${Buffer.from(keyPair.publicKey).toString("base64")}`);
+
+  //Set of messages we wish to sign
+  const messages = ["message1", "message2"];
+
+  console.log("Signing a message set of " + messages);
+
+  //Create the signature
+  const signature = blsSign({
+    keyPair,
+    messages: messages,
+  });
+
+  console.log(`Output signature base64 = ${Buffer.from(signature).toString("base64")}`);
+
+  //Verify the signature
+  const isVerified = blsVerify({
+    publicKey: keyPair.publicKey,
+    messages: messages,
+    signature,
+  });
+
+  const isVerifiedString = JSON.stringify(isVerified);
+  console.log(`Signature verified ? ${isVerifiedString}`);
+
+  //Derive a proof from the signature revealing the first message
+  const proof = blsCreateProof({
+    signature,
+    publicKey: keyPair.publicKey,
+    messages,
+    nonce: "nonce",
+    revealed: [0],
+  });
+
+  console.log(`Output proof base64 = ${Buffer.from(proof).toString("base64")}`);
+
+  //Verify the created proof
+  const isProofVerified = blsVerifyProof({
+    proof,
+    publicKey: keyPair.publicKey,
+    messageCount: messages.length,
+    messages: messages.slice(0, 1),
+    nonce: "nonce",
+    revealed: [0],
+  });
+
+  const isProofVerifiedString = JSON.stringify(isProofVerified);
+  console.log(`Proof verified ? ${isProofVerifiedString}`);
+};
+
+main();

sample/tsconfig.json

@@ -0,0 +1,18 @@
+{
+  "compilerOptions": {
+    "module": "commonjs",
+    "target": "es5",
+    "sourceMap": true,
+    "allowJs": false,
+    "moduleResolution": "node",
+    "strict": true,
+    "declaration": true,
+    "downlevelIteration": true,
+    "baseUrl": ".",
+    "esModuleInterop": true,
+    "resolveJsonModule": true,
+    "outDir": "./lib",
+    "types": ["jest", "node"]
+  },
+  "include": ["./src"]
+}