So all the other containers are in the Docker Swarm and we want to expose a real HTTP/S interface to clients outside of the Swarm, that makes sense. Clients have to get an API key first.

Build

Create your API key and put it in keys.properties

Let's produce a 256-bits key that we'll convert in an hex string to store and use with openssl hmac feature.

Alpine (Busybox):

dd if=/dev/urandom bs=32 count=1 2> /dev/null | xxd -pc 32

Linux:

dd if=/dev/urandom bs=32 count=1 2> /dev/null | xxd -ps -c 32

Put the id, key and groups in keys.properties and give the id and key to the client. The key is a secret. keys.properties looks like this:

#kappiid="id";kapi_key="key";kapi_groups="group1,group2";leave the rest intact
kapi_id="001";kapi_key="2df1eeea370eacdc5cf7e96c2d82140d1568079a5d4d87006ec8718a98883b36";kapi_groups="watcher";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}
kapi_id="002";kapi_key="50c5e483b80964595508f214229b014aa6c013594d57d38bcb841093a39f1d83";kapi_groups="watcher";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}
kapi_id="003";kapi_key="b9b8d527a1a27af2ad1697db3521f883760c342fc386dbc42c4efbb1a4d5e0af";kapi_groups="watcher,spender";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}
kapi_id="004";kapi_key="bb0458b705e774c0c9622efaccfe573aa30c82f62386d9435f04e9727cdc26fd";kapi_groups="watcher,spender";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}
kapi_id="005";kapi_key="6c009201b123e8c24c6b74590de28c0c96f3287e88cac9460a2173a53d73fb87";kapi_groups="watcher,spender,admin";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}
kapi_id="006";kapi_key="19e121b698014fac638f772c4ff5775a738856bf6cbdef0dc88971059c69da4b";kapi_groups="watcher,spender,admin";eval ugroups_${kapi_id}=${kapi_groups};eval ukey_${kapi_id}=${kapi_key}

You can have multiple keys, but be aware that this container has not been built to support thousands of API keys! Cyphernode should be used locally, not publicly as a service.

IP Addresses Whitelist (do not use for now)

Docker Swarm obfuscates real client IP, this feature is not ready for now

You can have an IP whitelist policy, denying everything except the explicit IP addresses you need. Edit ip-whitelist.conf file:

# Leave commented if you don't want to use IP whitelist

# List of white listed IP addresses...
#allow 45.56.67.78;
#deny all;

SSL

If you already have your certificates and keystores infra, you already know what to do and your can skip this section. Put your files in the bound volume (~/cyphernode-ssl/ see volume path in docker-compose.yml).

If not, you can create your keys and self-signed certificates.

mkdir -p ~/cyphernode-ssl/certs ~/cyphernode-ssl/private
openssl req -subj '/CN=localhost' -x509 -newkey rsa:4096 -nodes -keyout ~/cyphernode-ssl/private/key.pem -out ~/cyphernode-ssl/certs/cert.pem -days 365

If you don't want to use HTTPS, just copy default.conf instead of default-ssl.conf in Dockerfile.

Nota bene: If you self-sign the certificate, you have to trust the certificate on the client side by adding it to the Trusted Root Certification Authorities or whatever your client needs.

Build and run docker image

docker build -t authapi .

If you are using it independantly from the Docker stack (docker-compose.yml), you can run it like that:

docker run -d --rm --name authapi -p 80:80 -p 443:443 --network cyphernodenet -v "~/cyphernode-ssl/certs:/etc/ssl/certs" -v "~/cyphernode-ssl/private:/etc/ssl/private" authapi

FYI: Bearer token

Following JWT (JSON Web Tokens) standard, we build a bearer token that will be in the request header and signed with the secret key. We need this in the request header:

Authorization: Bearer <token>

...where token is:

token = hhh.ppp.sss

...where hhh is the header in base64, ppp is the payload in base64 and sss is the signature. Here are the expected formats and contents:

header = {"alg":"HS256","typ":"JWT"}
header64 = base64(header) = eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9Cg==

payload = {"id":"001","exp":1538528077}
payload64 = base64(payload) = eyJpZCI6IjAwMSIsImV4cCI6MTUzODUyODA3N30K

The "id" property is the client id and the "exp" property should be current epoch time + 10 seconds, like:

$((`date +"%s"`+10))

...so that the request will be expired in 10 seconds. That should take care of most Replay attacks if any. You should run nginx with TLS so that the replay attack can't be possible.

signature = hmacsha256(header64.payload64, key)

token = header64 + "." + payload64 + "." + signature

cURL example of an API invocation

Instruction should be in the form:

curl -v -H "Authorization: Bearer hhh.ppp.sss" localhost

10 seconds request expiration:

id="001";h64=$(echo "{\"alg\":\"HS256\",\"typ\":\"JWT\"}" | base64);p64=$(echo "{\"id\":\"$id\",\"exp\":$((`date +"%s"`+10))}" | base64);k="2df1eeea370eacdc5cf7e96c2d82140d1568079a5d4d87006ec8718a98883b36";s=$(echo "$h64.$p64" | openssl dgst -hmac "$k" -sha256 -r | cut -sd ' ' -f1);token="$h64.$p64.$s";curl -v -H "Authorization: Bearer $token" -k https://localhost/getbestblockhash

60 seconds request expiration:

id="001";h64=$(echo "{\"alg\":\"HS256\",\"typ\":\"JWT\"}" | base64);p64=$(echo "{\"id\":\"$id\",\"exp\":$((`date +"%s"`+60))}" | base64);k="2df1eeea370eacdc5cf7e96c2d82140d1568079a5d4d87006ec8718a98883b36";s=$(echo "$h64.$p64" | openssl dgst -hmac "$k" -sha256 -r | cut -sd ' ' -f1);token="$h64.$p64.$s";curl -v -H "Authorization: Bearer $token" -k https://localhost/getbestblockhash

Technicalities

h64=$(echo "{\"alg\":\"HS256\",\"typ\":\"JWT\"}" | base64)
p64=$(echo "{\"id\":\"001\",\"exp\":$((`date +"%s"`+10))}" | base64)
k="2df1eeea370eacdc5cf7e96c2d82140d1568079a5d4d87006ec8718a98883b36"
s=$(echo "$h64.$p64" | openssl dgst -hmac "$k" -sha256 -r | cut -sd ' ' -f1)
token="$h64.$p64.$s"