Turn your old smartphone into an offline hardware wallet

Robert Hoogendoorn
3 min readOct 7, 2019


Consumers with old smartphones laying in the closet can turn their old phone into offline hardware wallet for cryptocurrencies. First consumers need to dust off their phone. Then they download the Parity Signer v3.0 app for Android or iOS. Lastly they never put their phone online again. Parity Technologies announced their latest software in a press release.

The latest version of the app allows users to store Polkadot and Ethereum assets. For the best and safest conditions users should never connect the crypto hardware wallet to any online device. For example, don’t turn on WiFi functionality, but also never connect with another phone over Bluetooth or a computer through an USB cable.

Parity advises users to first clean their phone before installing. All software and accounts need to be removed. A factory reset is the best way to do this.

Offline hardware wallet not fully tested

Even though the technology for offline signing transactions is really cool, Parity Technologies does warn users. The company has not fully tested the offline hardware wallet yet. “We recommend using Parity Signer with caution: follow the official instructions and only store small amounts on it”, they write in the press release. Parity Signer is complete open-source. There has been an audit on small parts of the technology, but they are still planning an audit of the full application.

Parity Signer only works with Polkadot and the Ethereum blockchain. That’s because Parity Technologies was co-founded by Gavin Wood. He’s the former chief technology of Ethereum, and author of the Polkadot whitepaper. The other founder is the company is Jutta Steiner, former chief of security of Ethereum.

Smartphones moving into crypto

The Parity Signer gives a second life to old phones that are collecting dust anyway. Even though it’s cool to see old hardware getting a new purpose, it’s also interesting to see the direction of an entire industry. In the smartphone industry we’re seeing a move towards blockchain technology.

Several companies are developing cryptocurrencies powered by smartphones. A couple of Stanford researchers are building Pi Network. This cryptocurrency works like any other blockchain, but the validation of transactions is not done by miners but by smartphone users. They expect to launch their main net somewhere in 2020. Their network is currently in a testing phase, and sign-ups are only allowed through referrals.

On top of that there are even more ambitious development in regards to hardware. Samsung already has its Galaxy S10 smartphone on the market with integrated wallets. While blockchain startup Pundi Labs is working on a smartphone that works completely on blockchain technology.

China Telecom is expecting smartphones to become nodes in blockchain networks. The introduction of 5G internet will introduces a lot of new possibilities, as mobile internet will become many times faster. For example blockchain tech will help phone companies battle fraud, harassment and identity theft.

Originally published at NEDEROB.



Robert Hoogendoorn

Metaverse citizen, Web3 enthusiast, NFT collector. Learning about blockchain every day, sharing my knowledge and passion. Head of Content at DappRadar