Compare SSL files' key references

matchcert.sh

#!/bin/bash
#
# Compare SSL files' key references.
# Take a list of SSL certificate (.crt), certificate sign request
# (.csr) and/or key (.key) files, extract the modulus and compare, and
# return a nonzero exit code if they do not match.
#
check=''
for name in "$@"; do
    if [ "${name: -3}" == "crt" ]; then
	op="x509"
    fi
    if [ "${name: -3}" == "csr" ]; then
	op="req"
    fi
    if [ "${name: -3}" == "key" ]; then
	op="rsa"
    fi
    csum=`openssl $op -noout -modulus -in $name | openssl md5`
    if [ ${#check} -eq 0 ]; then
	check=$csum
    else
	if [ "$check" != "$csum" ]; then
	    echo "Key mismatch"
	    exit 1
	fi
    fi
done
echo "Keys match"