How to convert a private key to an RSA private key?

Let me explain my question first. I bought a certificate from a CA and used the following format to generate the csr and the private key:

openssl req -new -newkey rsa:2048 -nodes -keyout server.key -out server.csr

When I open the server.key file, I see that it begins with "-----BEGIN PRIVATE KEY-----"

I use the SSL cert on my server and everything looks fine.

Now I want to upload the same cert to AWS IAM so that I can use it for by beanstalk load balancer. I use the following command from this aws doc http://docs.aws.amazon.com/IAM/latest/UserGuide/InstallCert.html#SubmitCSRCertAuth

iam-servercertupload -b public_key_certificate_file  -k privatekey.pem -s certificate_object_name

I change the cert file names as required but keep getting this error: "400 MalformedCertificate Invalid Private Key."

The interesting thing is, on the aws doc page, the sample private key that they show starts with "-------Begin RSA Private Key--------"

Is there a way to convert my private key to an RSA private key using openssl?

Newer versions of OpenSSL say BEGIN PRIVATE KEY because they contain the private key + an OID that identifies the key type (this is known as PKCS8 format). To get the old style key (known as either PKCS1 or traditional OpenSSL format) you can do this:

openssl rsa -in server.key -out server_new.key

Alternately, if you have a PKCS1 key and want PKCS8:

openssl pkcs8 -topk8 -nocrypt -in privkey.pem

This may be of some help (do not literally write out the backslashes '\' in the commands, they are meant to indicate that "everything has to be on one line"):

It seems that all the commands (in grey) take any type of key file (in green) as "in" argument. Which is nice.

Here are the commands again for easier copy-pasting:

openssl rsa                                                -in $FF -out $TF
openssl rsa -aes256                                        -in $FF -out $TF
openssl pkcs8 -topk8 -nocrypt                              -in $FF -out $TF
openssl pkcs8 -topk8 -v2 aes-256-cbc -v2prf hmacWithSHA256 -in $FF -out $TF

and

openssl rsa -check -in $FF
openssl rsa -text  -in $FF

To Convert BEGIN OPENSSH PRIVATE KEY to BEGIN RSA PRIVATE KEY:

ssh-keygen -p -m PEM -f ~/.ssh/id_rsa