signature_digest_utility: command not found

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/signature_digest_utility - from package: vboot-utils

You may install the required package with command apt-get install {package}

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