Использование модуля perl Bytes :: Random :: Secure:
$ perl -MBytes::Random::Secure=random_bytes_hex -alne '
print join " ", @F[1..2], random_bytes_hex(24)
' file
<string> <string> 56fe375ade090e9838c13b5bbb799c2fac26d42da3f01691
<string> <string> 8bf748fb4d372e701af5ae0075a9de58c8ce3b05210c24bd
<string> <string> 345c58a5983e7bade8fed0311267daeea9ed314b1efe33d1
Модуль доступен в Ubuntu через пакет libbytes-random-secure-perl