OpenSSL unable to load Public Key

Question

Trying to encrypt a text message via command line on OSX Yosomite 10.10.2

Created public .pem key like this:

ssh-keygen -f ~/.ssh/id_rsa.pub -e -t PKCS8 > id_rsa.pem

If I try to encrypt myMessage.txt

openssl rsautl -encrypt -inkey ~/.ssh/id_rsa.pem -pubin -in ~/Desktop/myMessage.txt -out ~/Desktop/encrypted.txt

I get unable to load Public key

If I then type:

openssl asn1parse -in id_rsa.pem

Returns: Error: offset too large

But I have no idea how to fix it. What should I change to make it work?

Answer 1

Still don't know what went wrong in my question but found a solution:

1. Generate RSA key:

   $ openssl genrsa -out key.pem 1024 
   $ openssl rsa -in key.pem -text -noout
   

2. Save public key in pub.pem file:

   $ openssl rsa -in key.pem -pubout -out pub.pem 
   $ openssl rsa -in pub.pem -pubin -text -noout 
   

3. Encrypt some data:

   $ echo test test test > file.txt 
   $ openssl rsautl -encrypt -inkey pub.pem -pubin -in file.txt -out file.bin 
   

4. Decrypt encrypted data:

   $ openssl rsautl -decrypt -inkey key.pem -in file.bin 
   

It works like a charm