OpenSSH key pem和SSH2 key格式互转 （openssh 高版本）

openssl genkey 和 ssk-keygen 密钥的格式是不一样的
“RFC4716” (RFC 4716/SSH2 public or private key)
“PKCS8” (PEM PKCS8 public key)
ubuntu:
ssh-keygen -e -f ~/.ssh/id_rsa.pub > ~/.ssh/id_rsa_pub.pem
ssh-keygen -f ~/.ssh/id_rsa_pub.pem -i -m RFC4716 > ~/.ssh/id_rsa.pub
windows:
1)Use the puttyGen
2) Run puttygen and click generate
3) Run your mouse round the blank part for a while.
4) Enter a keyphrase (and repeat)
5) Click save public key and save it publickey
6) Click save private key and save it privatekey (extension gets added automatically, this is no good for spoon, but good for putty)
7) Click Conversions->Export OpenSSH key and save as sshkey.pem
8) In the main window is you key for pasting into OpenSSH authorized_keys file. Copy this in its entirety and past it into your ubuntu machine in /home//.ssh/authorized_keys file.
9) Ok, you can close putty key generator.
10) Utilize the .pem in the tool.
http://www.yinqisen.cn/blog-177.html