MobileCoin

About MobileCoin (MOB)

MobileCoin (MOB) is a privacy-focused payments cryptocurrency designed to run on mobile phones, with its own blockchain in which transaction details are hidden from everyone except sender and receiver. Its best-known use was as the payment currency in the Signal messenger's in-app payments feature, which Signal began beta testing in 2021. MOB matters as one of the few privacy coins built specifically for fast, phone-first payments rather than for desktop wallets or mining.

What Is MobileCoin?

MobileCoin is a standalone payment network with its own ledger. The MobileCoin repository describes it as "a privacy-preserving payments network designed for use on mobile devices" and as "a payment network with no central authority." The foundation's FAQ says it was built to address four issues: security, transaction speed, energy consumption and optimization for mobile devices.

The project's web presence has changed. mobilecoin.foundation now redirects to sentz.foundation, which presents the Sentz Foundation and "The Sentz protocol" while still hosting the MobileCoin FAQ and trusted node list. The company site mobilecoin.com now redirects to sentz.com, a stablecoin payments app. From these redirects it appears the MobileCoin brand is being folded into Sentz; the pages reviewed do not spell out what this means for the MOB token.

Who Founded MobileCoin? (History)

According to the foundation FAQ, MobileCoin Inc. was founded in 2017 by Josh Goldbard and Shane Glynn and is a venture-backed company based in San Francisco. The MobileCoin Foundation open-sourced the protocol in 2020, and the network went live on December 7, 2020.

On April 13, 2021, Signal published an update on beta testing payments in the United Kingdom, explaining that it chose MobileCoin because its design offered "fast, private, transactions at scale" that Signal could integrate as a non-custodial wallet feature. The foundation site lists a board (Sarah Novotny, Dr. David Bray, Renée DiResta, Alex Feerst) plus technical and policy advisory committees.

How MobileCoin Works

• UTXO model with hidden details: the ledger is a set of transaction outputs. Spending an output publishes a "key image" so it cannot be spent twice, without revealing which output was spent.
• CryptoNote-style privacy: the repository says transactions use CryptoNote techniques, so recipients are concealed behind one-time addresses.
• Two keys per account: a spend key and a view key, usually both derived from one piece of "root entropy".
• Consensus: the MobileCoin Consensus Protocol, a Byzantine-agreement protocol that the FAQ describes as a Federated Byzantine Agreement rather than proof of work. Validator nodes choose which other nodes they trust.
• Secure enclaves: consensus runs inside Intel SGX enclaves that remotely attest to each other before sharing transactions, adding defense in depth and forward secrecy.
• Fog: a component the repository labels "private payments for mobile devices", which is designed to let lightweight phone wallets work without keeping a full copy of the ledger.

The FAQ says most transactions complete in under ten seconds.

Key Ecosystem Components

1. Validator nodes Run consensus inside SGX. The foundation's trusted nodes page lists operators including Blockdaemon, The Long Now Foundation and MobileCoin Worldwide.

2. Watcher nodes Verify validator signatures on each block and keep a full ledger copy for wallets and exchanges (via mobilecoind).

3. Ledger distribution Full validators publish the blockchain to content delivery storage.

4. Wallets and integrations Signal's in-app wallet and MobileCoin's desktop wallet were the main documented user interfaces.

MOB Token Utility

MOB is the network's only currency and is used to send payments and pay transaction fees. The repository states that total value is "fixed by convention at a sum of 250 million mobilecoins," with each MOB divisible into 10^12 picomob. There is no mining or staking reward, since consensus does not rely on proof of work or proof of stake.

What Makes MobileCoin Unique?

MobileCoin combines private transactions with a design aimed at phones: fast confirmation, light clients through Fog, and simple wallet recovery. Its use of trusted execution hardware (Intel SGX) in consensus is unusual among privacy coins, and its integration into a mainstream encrypted messenger gave it a distribution path most privacy coins lack.

How MobileCoin Differs from Similar Chains

Monero also uses CryptoNote-derived privacy but relies on proof-of-work mining and full-node or remote-node wallets. Zcash uses zero-knowledge proofs with optional shielding. Secret Network uses secure enclaves for private smart contracts rather than for payments. MobileCoin's distinguishing choices are a fixed supply with no block rewards, federated consensus and a mobile-first client design.

Use Cases of MobileCoin

• Private peer-to-peer payments inside a messaging app.
• Everyday small payments where speed matters.
• Sending value across borders without exposing balances or history on a public ledger.

How MobileCoin Is Secured

Security rests on federated Byzantine agreement among validators, CryptoNote-style cryptography for privacy, and SGX enclaves as an extra layer. The repository is candid that SGX side-channel attacks have been published and patched, and says the design aims to protect privacy even if an enclave is compromised. The project's GitHub repository shows commits pushed as recently as September 2026.

Risks and Considerations

• Brand transition: the foundation and company sites now redirect to Sentz, and the future role of MOB there is not stated on the pages reviewed.
• Hardware trust: reliance on Intel SGX introduces a dependency on one chip vendor.
• Validator set: a federated model with a small, curated trusted-node list is less permissionless than proof-of-work networks.
• Regulatory pressure on privacy coins: some exchanges restrict privacy-focused assets.
• Limited venues: MOB is available on fewer platforms than larger coins.

Why MobileCoin Matters

MobileCoin is a serious attempt to make private digital cash usable on a phone, with published code, a live network since 2020 and a real integration with a widely used messenger. Its trade-offs (SGX, federated consensus) make it a useful contrast to other privacy designs.

Where Can You Buy MobileCoin?

MOB runs on its own chain, so it is traded on centralized exchanges that support MOB deposits and withdrawals rather than on Ethereum-style decentralized exchanges. The foundation FAQ pointed users outside the US to buymobilecoin.com and linked a guide on buying MOB in the US. Check current availability in your region.

Storage Options After Purchase

MOB needs a wallet that supports the MobileCoin network. Documented options include the Signal app's payments wallet (in supported regions) and MobileCoin's desktop wallet. Keep your recovery entropy or phrase offline, since the FAQ highlights wallet recovery as a core feature.

Related Coins

• Monero
• Zcash
• Dash
• Secret
• Firo