Firmare e cifrare email con kmail e gpg (kgpg)

Se ci sono problemi, forse è il gpg-agent che non è avviato correttamente. Usando kmail si suppone di essere in ambiente kde. Si risolve il problema avviando e chiudendo correttamente gpg-agent con la sessione kde inserendo due script nelle posizioni:

~/.kde/env/gpg-agent-start.sh

#!/bin/sh

GPG_AGENT=/usr/bin/gpg-agent
## Run gpg-agent only if not already running, and available
if [ -x "${GPG_AGENT}" ] ; then

  # gpg-agent uses ~/.gpg-agent-info by default, but we'll try to use
  # XDG_RUNTIME_DIR too for added safety
  GPG_AGENT_INFO_FILE=${XDG_RUNTIME_DIR:-${HOME}}/.gpg-agent-info

  # check validity of GPG_SOCKET (in case of session crash)
  if [ -f "${GPG_AGENT_INFO_FILE}" ]; then
    GPG_AGENT_PID=cat ${GPG_AGENT_INFO_FILE} | cut -f2 -d:
    GPG_PID_NAME=ps -p ${GPG_AGENT_PID} -o comm=
    if [ ! "x${GPG_PID_NAME}" = "xgpg-agent" ]; then
      rm -f "${GPG_AGENT_INFO_FILE}" 2>&1 >/dev/null
    else
      GPG_SOCKET=cat "${GPG_AGENT_INFO_FILE}" | cut -f1 -d: | cut -f2 -d=
      if ! test -S "${GPG_SOCKET}" -a -O "${GPG_SOCKET}" ; then
        rm -f "${GPG_AGENT_INFO_FILE}" 2>&1 >/dev/null
      fi
    fi
    unset GPG_AGENT_PID GPG_SOCKET GPG_PID_NAME
  fi

  if [ -f "${GPG_AGENT_INFO_FILE}" ]; then
    eval "$(cat "${GPG_AGENT_INFO_FILE}")"
    eval "$(cut -d= -f1 < "${GPG_AGENT_INFO_FILE}" | xargs echo export)"
    export GPG_TTY=$(tty)
  else
    eval "$(${GPG_AGENT} -s --daemon --write-env-file ${GPG_AGENT_INFO_FILE})"
  fi

  unset GPG_AGENT_INFO_FILE
fi

unset GPG_AGENT

~/.kde/shutdown/gpg-agent-shutdown.sh

#!/bin/sh

## The nice way
if test -n "${GPG_AGENT_INFO}"; then
  GPG_AGENT_PID=echo ${GPG_AGENT_INFO} | cut -d: -f2 && kill ${GPG_AGENT_PID} ||:
  unset GPG_AGENT_INFO
fi

## The not so nice way
## NOTE: a root login will kill all users' gpg-agents
#killall gpg-agent

## clean/remove .gpg-agent-info
## (we'll let the startup script reap stale entries)
#rm -f $HOME/.gpg-agent-info