SSL

Be your own SSL Certificate Authority.

This tutorial is based on the domain nextcloud.home. So change the domain to your specific domain.

It is also important that the domain address gets redirected from your router or use AdGuardHome. This can also be set in the /etc/hosts file of your computer, but to reach the domain on every device, it is easier to change this directly in the router or AdGuardHome:

nextcloud.domain SERVER-IP

mkcert is a simple tool for making locally-trusted development certificates. It requires no configuration.

pacman -S nss mkcert

mkcert -install

mkcert nextcloud.home

openssl genrsa -des3 -out rootCA.key 2048

openssl req -x509 -new -nodes -key rootCA.key -sha256 -days 1825 -out rootCA.pem

Change the following information as you wish. It appears when you view the certificate through your browser.

Country Name (2 letter code) [AU]:
State or Province Name (full name) [Some-State]:
Locality Name (eg, city) []:
Organization Name (eg, company) [Internet Widgits Pty Ltd]:
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:
Email Address []:

openssl genrsa -out nextcloud.home-key.pem 2048

openssl req -new -key nextcloud.home-key.pem -out nextcloud.home.pem

nano nextcloud.home.ext

authorityKeyIdentifier=keyid,issuer
basicConstraints=CA:FALSE
keyUsage = digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment
subjectAltName = @alt_names

[alt_names]
DNS.1 = nextcloud.home

Create the file in nano /etc/nginx/ssl/ssl.sh.

#!/bin/sh

if [ "$#" -ne 1 ]
then
  echo "Usage: Must supply a domain"
  exit 1
fi

DOMAIN=$1

openssl genrsa -out $DOMAIN-key.pem 2048
openssl req -new -key $DOMAIN-key.pem -out $DOMAIN.pem

cat > $DOMAIN.ext << EOF
authorityKeyIdentifier=keyid,issuer
basicConstraints=CA:FALSE
keyUsage = digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment
subjectAltName = @alt_names
[alt_names]
DNS.1 = $DOMAIN
EOF

openssl x509 -req -in $DOMAIN.pem -CA rootCA.pem -CAkey rootCA.key -CAcreateserial \
-out $DOMAIN.crt -days 825 -sha256 -extfile $DOMAIN.ext

chmod +x ssl.sh
./ssl.sh nextcloud.home

You'll need to create a rootCA.pem file on every device and copy the content of cat rootCA.pem file wherever you created it in section generating_the_private_key_and_root_certificate (manually).

If you used mkcert just run this command cat $(mkcert -CAROOT)/rootCA.pem.

sudo trust anchor --store rootCA.pem

Settings - Security - Encryption and credentials - Install a certificate

Check under:

Settings - Security - Trusted credentials - User

If “User trusted credentials” is not enough and you need the certificate in the system, follow the next lines. However, this requires a rooted device:

hashed_name=`openssl x509 -inform PEM -subject_hash_old -in rootCA.pem | head -1` && cp rootCA.pem $hashed_name.0
ls $hashed_name.0

adb root
adb shell mount -o rw,remount /
adb push $hashed_name.0 /system/etc/security/cacerts/
adb shell chmod 644 /system/etc/security/cacerts/$hashed_name.0
adb shell chown root:root /system/etc/security/cacerts/$hashed_name.0
adb shell reboot

You can also use the Magisk module MagiskTrustUserCerts (Android 13) or ConscryptTrustUserCerts (Android 14) which does the same as above.

Check also nginx

nano /etc/nginx/conf.d/ssl-params.conf

ssl_protocols TLSv1.3;
ssl_prefer_server_ciphers on;
ssl_ciphers "EECDH+AESGCM:EDH+AESGCM:AES256+EECDH:AES256+EDH";
ssl_ecdh_curve secp384r1;
ssl_session_cache shared:SSL:10m;

server {
        listen 80;
        listen [::]:80;
        server_name nextcloud.home;

        # enforce https
        return 301 https://$server_name:443$request_uri;
}

server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name nextcloud.home;

        ssl_certificate /etc/nginx/ssl/nextcloud.home.pem;
        ssl_certificate_key /etc/nginx/ssl/nextcloud.home-key.pem;
        include conf.d/ssl-params.conf;
    
        access_log /var/log/nginx/nextcloud.home_access_log;
        error_log /var/log/nginx/nextcloud.home-error_log;

        location / {
                your things;
        }
}