Regex to match PEM file headers according to OpenSSL pem.h

For each input pem string:

1. check if it contains PEM header line
2. check if it contains corresponding footer line
3. join the in-between lines and try decoding it as base64
4. return the matched label, i.e. RSA PRIVATE KEY and type, i.e. PRIVATE.

Match and return { label, type } or undefined:

• Property label could be :
  • PRIVATE KEY
  • RSA PRIVATE KEY
  • ANY PRIVATE KEY
  • ENCRYPTED PRIVATE KEY
  • PUBLIC KEY
  • ...
• Property type:
  • PRIVATE
  • PUBLIC

Match and return { label, type } or undefined:

• Property label could be:
  • CERTIFICATE
  • TRUSTED CERTIFICATE
  • CERTIFICATE REQUEST
  • NEW CERTIFICATE REQUEST
  • X509 CRL
• Property type:
  • CERTIFICATE
  • REQUEST
  • CRL

Match only begin header and return { label, type } or undefined

Match only end footer and return { label, type } or undefined

Match only begin header and return { label } or undefined

Match only end footer and return { label } or undefined

Match and return the private key label or undefined.

Match and return the private key label or undefined.

Match and return the certificate label or undefined.

Match and return the certificate request label or undefined.

Match and return the CRL label or undefined.