From 0ee35e49465b404f6f35aa70d4c75ccf09167acf Mon Sep 17 00:00:00 2001
From: Matthew Aaron Raymer <matthew.raymer@anomalistdesign.com>
Date: Tue, 3 Jan 2023 12:35:41 +0800
Subject: [PATCH] Added variation of accessToken method carried over from
 endorser-mobile

---
 src/libs/crypto/index.ts | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/libs/crypto/index.ts b/src/libs/crypto/index.ts
index 8068260..d386ef4 100644
--- a/src/libs/crypto/index.ts
+++ b/src/libs/crypto/index.ts
@@ -4,6 +4,8 @@ import { getRandomBytesSync } from "ethereum-cryptography/random";
 import { entropyToMnemonic } from "ethereum-cryptography/bip39";
 import { wordlist } from "ethereum-cryptography/bip39/wordlists/english";
 import { HDNode } from "@ethersproject/hdnode";
+import * as didJwt from 'did-jwt';
+import * as u8a from 'uint8arrays'
 
 /**
  *
@@ -37,7 +39,14 @@ export const newIdentifier = (
   };
 };
 
-export const deriveAddress = (
+
+/**
+ *
+ *
+ * @param {string} mnemonic
+ * @return {*}  {[string, string, string, string]}
+ */
+const deriveAddress = (
   mnemonic: string
 ): [string, string, string, string] => {
   const UPORT_ROOT_DERIVATION_PATH = "m/7696500'/0'/0'/0'";
@@ -52,6 +61,7 @@ export const deriveAddress = (
   return [address, privateHex, publicHex, UPORT_ROOT_DERIVATION_PATH];
 };
 
+
 /**
  *
  *
@@ -63,3 +73,27 @@ export const createIdentifier = (): string => {
 
   return mnemonic;
 };
+
+
+/**
+ * Retreive an access token
+ *
+ * @param {IIdentifier} identifier
+ * @return {*} 
+ */
+const accessToken = async (identifier: IIdentifier) => {
+  const did: string = identifier.did;
+  const privateKeyHex: string = identifier.keys[0].privateKeyHex as string;
+  const input = privateKeyHex.startsWith('0x') ? privateKeyHex.substring(2) : privateKeyHex;
+  const privateKeyBytes = u8a.fromString(input.toLowerCase(), 'base16')
+
+  const signer = didJwt.ES256KSigner(privateKeyBytes, true);
+
+  const nowEpoch = Math.floor(Date.now() / 1000);
+  const endEpoch = nowEpoch + 60; // add one minute
+
+  const uportTokenPayload = { exp: endEpoch, iat: nowEpoch, iss: did };
+  const alg = undefined; // defaults to 'ES256K', more standardized but harder to verify vs ES256K-R
+  const jwt: string = await didJwt.createJWT(uportTokenPayload, { alg, issuer: did, signer });
+  return jwt;
+};
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