xsec-templatesign: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/xsec-templatesign - from package: xml-security-c-utils

You may install the required package with command apt-get install {package}
Error in other languages:
xsec-templatesign: bevel nie gevind nie
xsec-templatesign: comandă negăsită
xsec-templatesign: comando não encontrado
xsec-templatesign: commande introuvable
xsec-templatesign: command not found
xsec-templatesign: käsku ei ole
xsec-templatesign: không tìm thấy lệnh
xsec-templatesign: komanda nerasta
xsec-templatesign: Kommando nicht gefunden.
xsec-templatesign: kommandot finns inte
xsec-templatesign: komut yok
xsec-templatesign: nie znaleziono polecenia
xsec-templatesign: níor aimsíodh an t-ordú
xsec-templatesign: no se encontró la orden
xsec-templatesign: no s'ha trobat l'ordre
xsec-templatesign: opdracht niet gevonden
xsec-templatesign: parancs nem található
xsec-templatesign: perintah tidak ditemukan
xsec-templatesign: príkaz nenájdený
xsec-templatesign: příkaz nenalezen
xsec-templatesign: команда не найдена
xsec-templatesign: командата не е открита
xsec-templatesign: 命令找不到
xsec-templatesign: コマンドが見つかりません