getBitcoinPrivateKeychain(): BIP32 { 
   return this.rootNode
     .deriveHardened(BITCOIN_BIP_44_PURPOSE)
     .deriveHardened(BITCOIN_COIN_TYPE)
     .deriveHardened(BITCOIN_ACCOUNT_INDEX)
 }

 static getAppsNode(identityNode: BIP32): BIP32 {
   return identityNode.deriveHardened(APPS_NODE_INDEX)
 }

 getIdentityPrivateKeychain(): BIP32 { 
   return this.rootNode
     .deriveHardened(IDENTITY_KEYCHAIN)
     .deriveHardened(BLOCKSTACK_ON_BITCOIN)
 }

 toBase58(): string {
   return this.rootNode.toBase58()
 }