A growing chorus of Bitcoin proponents is urging the privacy-focused messaging app Signal to integrate Bitcoin, spearheaded by a new campaign called "Bitcoin for Signal". The initiative aims to enable Bitcoin payments within the app, leveraging the Cashu protocol for enhanced privacy.
The call for Bitcoin integration has been amplified by prominent figures in the Bitcoin community, including Jack Dorsey, former CEO of Twitter and a known Bitcoin advocate. Dorsey retweeted a post from the pseudonymous Bitcoin developer Cashu, who is leading the "Bitcoin for Signal" campaign, signaling his support for the initiative. "Signal should use Bitcoin," Dorsey posted on X. David Marcus, former president of PayPal and current CEO of Lightspark, echoed this sentiment, suggesting that "all non-transactional apps should connect to Bitcoin".
The "Bitcoin for Signal" campaign proposes implementing Cashu's "Chaumian Ecash" solution. This would integrate Bitcoin with the Cashu protocol to facilitate Bitcoin payments within Signal, emphasizing user privacy. The Bitcoin for Signal website states, "Bitcoin belongs to Signal. Cashu ecash enables truly private Bitcoin payments inside the world's most trusted encryption messenger".
Peter Todd, a Bitcoin developer, has also voiced his support for the campaign. Todd suggests that Bitcoin should replace, or at least augment, Signal's existing cryptocurrency payment solution, MobileCoin (MOB). He criticized MobileCoin for being overly centralized and difficult to acquire, stating, "The Signal app needs to accept reality and just add Bitcoin support".
Signal integrated MobileCoin in April 2021. However, it has faced criticism due to its centralized nature and a small set of validators. Several figures in the Bitcoin community also support Bitcoin for Signal, including pseudonymous Bitcoin developer Calle and Satoshi Labs co-founder Pavol Rusnak.
Signal, boasting approximately 70 million monthly active users, could become a significant platform for peer-to-peer Bitcoin transactions if the integration is successful. The current price of Bitcoin is around $107,938.
Despite the enthusiasm, some critics have raised concerns about using Bitcoin in a privacy-focused app like Signal. They argue that Bitcoin's public blockchain could potentially compromise user privacy, suggesting privacy-centric alternatives like Monero and Zcash. José Pedro Sousa, an engineer at Aztec Network, questioned the use of a public blockchain for a privacy-centric chat application. Techlore, a digital rights advocacy group, has also cautioned that Bitcoin integration might jeopardize Signal users' privacy.
Signal has been "actively exploring the addition of payments" and has considered integrating MobileCoin, a privacy coin built on the Stellar blockchain. Moxie Marlinspike, Signal's CEO, has served as an advisor to MobileCoin. However, some Signal employees reportedly view cryptocurrency exploration as risky, potentially attracting "bad actors" and regulatory scrutiny. Marlinspike stated that if Signal were to implement payments, they would carefully consider how to do it.
Signal already has a cryptocurrency wallet functionality for in-app payments. As of January 2022, MobileCoin is the only supported payment method.
