What Does It Mean to Be a Signal Competitor?

The article discusses the criteria for a communication product to be considered a competitor to Signal, particularly from a cryptographic and security perspective. The author emphasizes that any messaging app must be open source and implement end-to-end encryption without any option for transmitting plaintext. This disqualifies many popular apps like Matrix, Telegram, and XMPP + OMEMO. The author highlights the importance of how encryption is implemented, noting that Signal's use of AES-256-CBC with HMAC-SHA256 is a standard that competitors should aim to match. Additionally, the complexity of group messaging protocols and key management is addressed, with a recommendation for regular audits by cryptography firms to ensure security. The author warns against adding features that could compromise user privacy and stresses that any app that prioritizes features over security cannot be considered a viable alternative to Signal. The post concludes by urging readers not to recommend messaging apps that do not meet these stringent criteria as alternatives to Signal, reinforcing the need for a focused discussion on cryptographic security in messaging applications.