I'm having .crt and .pem file with
-----BEGIN CERTIFICATE-----
MIIFSDCCBDCg........................................
-----END CERTIFICATE-----
and I want RSA key from this file.
anyone is having any idea that how we can do that.
I have used below command one by one
openssl rsa -in XXX.crt -out input1.der -outform DER
openssl rsa -in input1.der -inform DER -out key.pem -outform PEM
But, It gives error:
unable to load Private Key 140331982231200:error:0906D06C:PEM
routines:PEM_read_bio:no start line:pem_lib.c:703:Expecting: ANY PRIVATE KEY
and I have also used different command but it give above error.
-----BEGIN CERTIFICATE-----
MIIFSDCCBDCg........................................
-----END CERTIFICATE-----
This is a certificate in pem format which is a wrapper over public key. A Certificate is supposed to be public and can be distributed, but private key (as the name suggest) is supposed to be kept secret. So a certificate can never contain a private key.
You mentioned, you have a ´.pem´ file too. What is it's content? Does it start with -----BEGIN RSA PRIVATE KEY-----. If yes, it would be your private key.
The command you are trying: openssl rsa It expects a private key in input, but you are supplying it a certificate. Hence the error.
You can't get a private key from a certificate, because the private key isn't in the certificate, and you can't get it from a PEM file unless the PEM file contains it, which ain't necessarily so,
来源：https://stackoverflow.com/questions/43384627/how-to-get-rsa-key-from-begin-certificate-from-crt-and-pem-file