JWKS decoder for Vaccine Certificate JWKS

JWKS-DECODE.sh

#!/bin/sh
#
# Following two commands required
# jq -- https://stedolan.github.io/jq/ # or brew install jq
# base64 -- https://www.fourmilab.ch/webtools/base64/  # or brew install base64
#
# This code stored as public gist at:
# https://gist.github.com/shigeya/6a9288286da274d4c25a1e4a584df5f5

curl -s -O https://vc.vrs.digital.go.jp/issuer/.well-known/jwks.json

jq '.keys[0]["x5c"][0]' < jwks.json | sed -e s/\"//g > issuer.der.base64url
jq '.keys[0]["x5c"][1]' < jwks.json | sed -e s/\"//g > ca.der.base64url
jq '.keys[0]["x5c"][2]' < jwks.json | sed -e s/\"//g > root.der.base64url

for i in issuer ca root
do
	base64 -d < $i.der.base64url > $i.der

	echo "# $i"
	openssl x509 -inform der -in $i.der -text > $i.text
	cat $i.text
done

exit 0