Starting from plasma-vault 6.4.0 it only supports gocryptfs backend. It's a hard dependency. All packages (including 6.7.4-1 from sid) list gocryptfs as a suggestion, rather than dependency (see below).
cryfs dependency should be replaced with gocryptfs, and the latter should be removed from suggestions. Installing gocryptfs manually fixes the issue. Relevant thread: https://www.mail-archive.com/[email protected]/msg1048144.html $ apt-cache show plasma-vault Package: plasma-vault Version: 6.7.4-1 Installed-Size: 1621 Maintainer: Debian Qt/KDE Maintainers <[email protected]> Architecture: amd64 Depends: cryfs, plasma-desktoptheme, qml6-module-org-kde-kirigami, qml6-module-qtquick, qml6-module-qtquick-controls, qml6-module-qtquick-layouts, plasma-version-base-6.7, kio6, libc6 (>= 2.32), libgcc-s1 (>= 3.0), libkf6configcore6 (>= 6.26.0~), libkf6coreaddons6 (>= 6.26.0~), libkf6dbusaddons6 (>= 6.26.0~), libkf6i18n6 (>= 6.26.0~), libkf6kiocore6 (>= 6.26.0~), libkf6kiogui6 (>= 6.26.0~), libkf6kiowidgets6 (>= 6.26.0~), libkf6networkmanagerqt6 (>= 6.26.0~), libkf6se rvice-bin, libkf6service6 (>= 6.26.0~), libkf6widgetsaddons6 (>= 6.10.0~), libplasma7 (>= 6.7.0~), libplasmaactivities7 (>= 6.7.0~), libprocesscore11 (>= 4:6.6~), libqt6core6t64 (>= 6.10.2), libqt6dbus6 (>= 6.10.0~), libqt6gui6 (>= 6.10 .0~), libqt6widgets6 (>= 6.10.0~), libstdc++6 (>= 14) Suggests: gocryptfs Description-en: Plasma applet and services for creating encrypted vaults File encryption widget. Description-md5: 765ef951192334e351074b38ae0bfa82 Homepage: https://invent.kde.org/plasma/plasma-vault Tag: uitoolkit::qt Section: kde Priority: optional Filename: pool/main/p/plasma-vault/plasma-vault_6.7.4-1_amd64.deb Size: 341148 MD5sum: eacc79a5584bb7ade1da1460c5e07728 SHA256: 3e0fd9989adcb66f94519ed23e24f515c8d54af57ba522a18598220c1e9fa308
