experiments with using v3 onions with client auth (as of tor 0.3.5.X)

onion-svc-v3-client-auth.sh

#!/bin/bash

# needs openssl 1.1+
# needs `basez` https://manpages.debian.org/testing/basez/base32hex.1.en.html
#   (but something else that decodes the base64 and re-encodes the raw key bytes
#    to base32 is probably fine too)

##### generate a key

openssl genpkey -algorithm x25519 -out /tmp/k1.prv.pem

##### re-formatting the keys into base32 in a way that tor likes:

# basically take the base64pem from the above key file, decode it to raw binary data,
# strip the PKCS header (key is final 32bytes of the raw data), re-encode it into base32,
# strip the "=" padding

cat /tmp/k1.prv.pem |\
    grep -v " PRIVATE KEY" |\
    base64pem -d |\
    tail --bytes=32 |\
    base32 |\
    sed 's/=//g' > /tmp/k1.prv.key

openssl pkey -in /tmp/k1.prv.pem -pubout |\
    grep -v " PUBLIC KEY" |\
    base64pem -d |\
    tail --bytes=32 |\
    base32 |\
    sed 's/=//g' > /tmp/k1.pub.key

##### do the outputs

echo "X25519 Private Key:"
cat /tmp/k1.prv.key

echo
echo "X25519 Public Key: (give this to the onion service)"
cat /tmp/k1.pub.key

echo
echo "====="
echo "Tor client configuration"
echo "====="
echo "Make sure you have ClientOnionAuthDir set in your torrc. In the"
echo "<ClientOnionAuthDir> directory, create an '.auth_private' file for the"
echo "onion service corresponding to this key (i.e. 'bob_onion.auth_private')."
echo "The contents of the <ClientOnionAuthDir>/<user>.auth_private file should"
echo "look like:"
echo
echo "    <56-char-onion-addr-without-.onion-part>:descriptor:x25519:`cat /tmp/k1.prv.key`"
echo
echo "i.e.:"
echo "    p53lf57qovyuvwsc6xnrppyply3vtqm7l6pcobkmyqsiofyeznfu5uqd:descriptor:x25519:`cat /tmp/k1.prv.key`"

echo
echo "====="
echo "Onion service configuration"
echo "====="
echo "Inside the HiddenServiceDir for this onion service, create an"
echo "/authorized_clients/ subdirectory and a '.auth' file for the user (i.e."
echo "'alice.auth'). The contents of the <HiddenServiceDir>/authorized_clients/<username>.auth"
echo "file should look like:"
echo
echo "    descriptor:x25519:`cat /tmp/k1.pub.key`"

rm -f /tmp/k1.pub.key /tmp/k1.prv.key /tmp/k1.prv.pem

output-example.txt

X25519 Private Key:
BBBEAUAO3PIFAH7SBGBI6A2QFAZBXG2NVN7HMBXFCZENJVF6C5AQ

X25519 Public Key: (give this to the onion service)
SUCXD2A4YRK4JQ37QCIAQXGASQWVLFH45XENCC5YDZFR6RIT6ETA

=====
Tor client configuration
=====
Make sure you have ClientOnionAuthDir set in your torrc. In the
<ClientOnionAuthDir> directory, create an '.auth_private' file for the
onion service corresponding to this key (i.e. 'bob_onion.auth_private').
The contents of the <ClientOnionAuthDir>/<user>.auth_private file should
look like:

    <56-char-onion-addr-without-.onion-part>:descriptor:x25519:BBBEAUAO3PIFAH7SBGBI6A2QFAZBXG2NVN7HMBXFCZENJVF6C5AQ

i.e.:
    p53lf57qovyuvwsc6xnrppyply3vtqm7l6pcobkmyqsiofyeznfu5uqd:descriptor:x25519:BBBEAUAO3PIFAH7SBGBI6A2QFAZBXG2NVN7HMBXFCZENJVF6C5AQ

=====
Onion service configuration
=====
Inside the HiddenServiceDir for this onion service, create an
/authorized_clients/ subdirectory and a '.auth' file for the user (i.e.
'alice.auth'). The contents of the <HiddenServiceDir>/authorized_clients/<username>.auth
file should look like:

    descriptor:x25519:SUCXD2A4YRK4JQ37QCIAQXGASQWVLFH45XENCC5YDZFR6RIT6ETA

Hi, please pull my version https://gist.github.com/stokito/8d1fb41a3834deaf27f5619dc2bbb061
I adopted the script for OpenWrt.

Changes:

• Use /bin/sh shebang. No need to use bash here
• The base64pem replaced with plain base64. The string is anyway smaller than 76. The base64pem is not available on OpenWrt.
• Use tail -c 32 for posix as @nyxnor mentioned. The BusyBox's tail doesn't have --bytes

Thank you.

https://kushaldas.in/posts/python-function-to-generate-tor-v3-onion-service-authentication-keys.html

Turned out that for OpenWrt there is package tor-gencert for "Generate certs and keys for Tor directory authorities".
Also see https://openwrt.org/docs/guide-user/services/tor/hs#client_authorization_old