SSL

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• Networking 4 All - Most used OpenSSL commands

Split PKCS#12 certificate into CA / Cert / Private key

Use openssl pkcs12 to split a pkcs#12 data into the CA / certificates / private keys component. By default, PKCS#12 produces PEM files [1].

openssl pkcs12 -in mywindowscert.pfx -nocerts -out mycert.key
openssl pkcs12 -in mywindowscert.pfx -clcerts -nokeys -out mycert.crt.pem
openssl pkcs12 -in mywindowscert.pfx -cacerts -nokeys -out mycert.ca.pem

Checking Certificate Chain with OpenSSL

Checking A Remote Certificate Chain With OpenSSL

Change .p12 / .pfx password

Say you have a private key / certificate file mycert.pfx, and you want to change its password:

# Strangely we cannot pipe output of 1st command into 2nd (error 'No certificate matches private key')
openssl pkcs12 -in mycert.pfx -out mycert.pem -nodes         # Don't encrypt private key at all
openssl pkcs12 -export -in mycert.pem -out mycert-new.pfx
rm mycert.pem                                               # DON'T FORGET THIS!

Extract key from .p12/ .pfx

• openssl pkcs12 takes a file in pkcs#12 format (.p12/.pfx) and produces a file in PEM format, that is parseable with openssl rsa. The PEM may contain either private key, certificates, root certificates or even public keys.

openssl pkcs12 -in mycert.pfx -out mycert.pem -nocerts -nodes  # Don't encrypt private key at all, don't output certificates
openssl rsa -noout -modulus -in mycert.pem                     # To extract the modulus
openssl rsa -noout -text -in mycert.pem                        # To extract all the fields