implements ledger multisig backup command

adds a CLI command, 'wallet:multisig:ledger:backup', to create an encrypted
backup of multisig keys from the ironfish dkg ledger app

users can restore the keys to their ledger app if they reinstall the app on
their device or overwrite the multisig keys in the app

ironfish-cli/src/commands/wallet/multisig/ledger/backup.ts

@@ -0,0 +1,28 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+import { IronfishCommand } from '../../../../command'
+import { Ledger } from '../../../../utils/ledger'
+
+export class MultisigLedgerBackup extends IronfishCommand {
+  static description = `Backup encrypted multisig keys from a Ledger device`
+
+  async start(): Promise<void> {
+    const ledger = new Ledger(this.logger)
+    try {
+      await ledger.connect(true)
+    } catch (e) {
+      if (e instanceof Error) {
+        this.error(e.message)
+      } else {
+        throw e
+      }
+    }
+
+    const encryptedKeys = await ledger.dkgBackupKeys()
+
+    this.log()
+    this.log('Encrypted Ledger Multisig Backup:')
+    this.log(encryptedKeys.toString('hex'))
+  }
+}

ironfish-cli/src/utils/ledger.ts

@@ -305,6 +305,18 @@ export class Ledger {
 
     return signature
   }
+
+  dkgBackupKeys = async (): Promise<Buffer> => {
+    if (!this.app) {
+      throw new Error('Connect to Ledger first')
+    }
+
+    this.logger.log('Please approve the request on your ledger device.')
+
+    const { encryptedKeys } = await this.tryInstruction(this.app.dkgBackupKeys())
+
+    return encryptedKeys
+  }
 }
 
 function isResponseAddress(response: KeyResponse): response is ResponseAddress {