Update with our own SimpleSigner

src/libs/crypto/index.ts

@@ -5,8 +5,44 @@ 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 { Signer } from "did-jwt";
 import * as u8a from "uint8arrays";
 
+export function hexToBytes(s: string): Uint8Array {
+  const input = s.startsWith("0x") ? s.substring(2) : s;
+  return u8a.fromString(input.toLowerCase(), "base16");
+}
+
+export function fromJose(signature: string): {
+  r: string;
+  s: string;
+  recoveryParam?: number;
+} {
+  const signatureBytes: Uint8Array = base64ToBytes(signature);
+  if (signatureBytes.length < 64 || signatureBytes.length > 65) {
+    throw new TypeError(
+      `Wrong size for signature. Expected 64 or 65 bytes, but got ${signatureBytes.length}`
+    );
+  }
+  const r = bytesToHex(signatureBytes.slice(0, 32));
+  const s = bytesToHex(signatureBytes.slice(32, 64));
+  const recoveryParam =
+    signatureBytes.length === 65 ? signatureBytes[64] : undefined;
+  return { r, s, recoveryParam };
+}
+
+export function bytesToHex(b: Uint8Array): string {
+  return u8a.toString(b, "base16");
+}
+
+export function base64ToBytes(s: string): Uint8Array {
+  const inputBase64Url = s
+    .replace(/\+/g, "-")
+    .replace(/\//g, "_")
+    .replace(/=/g, "");
+  return u8a.fromString(inputBase64Url, "base64url");
+}
+
 /**
  *
  *
@@ -111,3 +147,23 @@ export const sign = async (privateKeyHex: string) => {
 
   return signer;
 };
+
+/**
+ *  The SimpleSigner returns a configured function for signing data.
+ *
+ *  @example
+ *  const signer = SimpleSigner(process.env.PRIVATE_KEY)
+ *  signer(data, (err, signature) => {
+ *    ...
+ *  })
+ *
+ *  @param    {String}         hexPrivateKey    a hex encoded private key
+ *  @return   {Function}                     a configured signer function
+ */
+export const SimpleSigner = async (hexPrivateKey: string): Promise<Signer> => {
+  const signer = didJwt.ES256KSigner(hexToBytes(hexPrivateKey), true);
+  return async (data) => {
+    const signature = (await signer(data)) as string;
+    return fromJose(signature);
+  };
+};