Certificates

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Source: sslshopper.com

General OpenSSL Commands

  • Generate a new private key and Certificate Signing Request
openssl req -out CSR.csr -new -newkey rsa:2048 -nodes -keyout privateKey.key
  • Generate a self-signed certificate
openssl req -x509 -sha256 -nodes -days 365 -newkey rsa:2048 -keyout privateKey.key -out certificate.crt
  • Generate a certificate signing request (CSR) for an existing private key
openssl req -out CSR.csr -key privateKey.key -new
  • Generate a certificate signing request based on an existing certificate
 openssl x509 -x509toreq -in certificate.crt -out CSR.csr -signkey privateKey.key
  • Remove a passphrase from a private key
openssl rsa -in privateKey.pem -out newPrivateKey.pem

Checking Using OpenSSL

  • Check a Certificate Signing Request (CSR)
openssl req -text -noout -verify -in CSR.csr
  • Check a private key
openssl rsa -in privateKey.key -check
  • Check a certificate
openssl x509 -in certificate.crt -text -noout
  • Check a PKCS#12 file (.pfx or .p12)
openssl pkcs12 -info -in keyStore.p12

Debugging Using OpenSSL

  • Check an MD5 hash of the public key to ensure that it matches with what is in a CSR or private key
openssl x509 -noout -modulus -in certificate.crt | openssl md5
openssl rsa -noout -modulus -in privateKey.key | openssl md5
openssl req -noout -modulus -in CSR.csr | openssl md5
  • Check an SSL connection. All the certificates (including Intermediates) should be displayed
openssl s_client -connect www.paypal.com:443

Converting Using OpenSSL

  • Convert a DER file (.crt .cer .der) to PEM
openssl x509 -inform der -in certificate.cer -out certificate.pem
  • Convert a PEM file to DER
openssl x509 -outform der -in certificate.pem -out certificate.der
  • Convert a PKCS#12 file (.pfx .p12) containing a private key and certificates to PEM
openssl pkcs12 -in keyStore.pfx -out keyStore.pem -nodes

You can add -nocerts to only output the private key or add -nokeys to only output the certificates.

  • Convert a PEM certificate file and a private key to PKCS#12 (.pfx .p12)
openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt


Troubleshooting



References





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