Alternatives to Kleopatra
A KDE certificate manager and front end for OpenPGP and S/MIME encryption and signing. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Kleopatra
A KDE certificate manager and front end for OpenPGP and S/MIME encryption and signing.
Replacements
Listings that take over the same core job as Kleopatra.
Gpg4win
GnuPG packaged for Windows with the Kleopatra key manager, for signing and encrypting files and email.
Gpg4win bundles Kleopatra with GnuPG for Windows and adds Outlook integration through GpgOL and Explorer integration through GpgEX, but it is Windows only.
KGpg
A KDE graphical front end for GnuPG that manages keys and encrypts files and text.
KGpg is a simpler KDE front end for GnuPG showing signatures, trust and expiry at a glance, but it lacks S/MIME support and has fewer features.
Seahorse
GNOME's password and encryption key manager for the system keyring, PGP keys and SSH keys.
Seahorse is GNOME's key manager covering PGP keys, SSH keys and the system keyring, without the S/MIME certificate handling Kleopatra offers.
GPG Suite
An OpenPGP toolkit for macOS for encrypting, signing and verifying files and email.
GPG Suite runs on macOS only, providing the GPG Keychain key manager and Apple Mail integration, with a paid subscription for GPG Mail.
GnuPG
Complete free implementation of the OpenPGP standard.
GnuPG provides the same OpenPGP operations from the command line with smartcard support through its agent, but without a graphical certificate manager.
Sequoia PGP
An OpenPGP implementation in Rust with the sq command-line tool for encrypting, signing and managing keys.
Sequoia PGP is a Rust OpenPGP toolkit using the sq command-line tool, trading the graphical interface and S/MIME support for a memory-safe implementation.
Similar software
Related functionality, not a direct replacement.
OpenKeychain
An open-source Android app that manages OpenPGP keys and encrypts, decrypts and signs messages and files.
Mailvelope
Browser extension that adds OpenPGP encryption to webmail.
OpenSSL
Work with certificates and cryptography using a widely used toolkit.
FlowCrypt
A browser extension that adds OpenPGP encryption for sending and receiving email in Gmail.