Create a share directory that requires user authentication.

sudo groupadd security
 
mkdir /home/security
 
chgrp security /home/security
 
chmod 770 /home/security
 
sudo vi /etc/samba/smb.conf

Edit the Samba config file:

/etc/samba/smb.conf

# line 25: add
unix charset = UTF-8
 
# line 30: change (Windows' default)
workgroup = WORKGROUP
 
# line 51: uncomment and change IP address you allow
interfaces = 127.0.0.0/8 10.0.0.0/24
 
# line 58: uncomment
bind interfaces only = yes
 
# add to the end any share name you like
 
[Security]
    path = /home/security
    writable = yes
    create mode = 0770
    directory mode = 0770
    # guest not allowed
    guest ok = no
    # allow users only in [security] group
    valid users = @security

Add user in Samba

smbpasswd -a peter

will prompt for a password:

New SMB password:     # set password
 
Retype new SMB password:
Added user ubuntu.

Add the user to the security group:

sudo usermod -G security peter

Restart Samba

sudo systemctl restart smbd