Drawing the 𝖫𝖨𝖭𝖤: Cryptographic Analysis and Security Improvements for the 𝖫𝖨𝖭𝖤 E2EE Protocol. - Benjamin Dowling; Prosanta Gope; Mehr U. Nisa; Bhagya Wimalasiri (IACR Commun. Cryptol., 2026)