How do I format a public key?
The OpenSSH public key format¶ The public key saved by ssh-keygen is written in the so-called SSH-format, which is not a standard in the cryptography world. It’s structure is , where the part of the format is encoded with Base64.
What format is SSH-keygen?
The supported key formats are: “RFC4716” (RFC 4716/SSH2 public or private key), “PKCS8” (PKCS8 public or private key) or “PEM” (PEM public key). By default OpenSSH will write newly-generated private keys in its own format, but when converting public keys for export the default format is “RFC4716”.
How to convert SSH public key from PEM to der?
OpenSSH public key format is different from PEM format. You have to run ssh-keygen to convert it. Then convert it to DER format using openssl rsa. Note that you also have to specify -RSAPublicKey_in (not -pubin) and -RSAPublicKey_out to keep it to be RSA Public Key (PKCS#1).
How to convert a ssh-keygen public key into a.pub file?
Obviously I cannot simply use the ASCII string in the ssh-keygen <>.pub key file as it is in SSH file format or I perhaps SubjectPublicKeyInfo structure. I found a converter in php on the web which will convert the contents of the public key into a base64 PEM ASCII string format.
How to convert OpenSSL key to SSH key?
No need to compile stuff. You can do the same with ssh-keygen: will read the public key in openssl format from pub1key.pub and output it in OpenSSH format. Note: In some cases you will need to specify the input format: -m key_format Specify a key format for the -i (import) or -e (export) conversion options.
How to convert OpenSSL public key to PEM format?
If you have an RSA key pair in DER format, you may want to convert it to PEM to allow the format conversion below: Here is C code to convert from an OpenSSL public key to an OpenSSH public key. You can grab the code from this link and compile it yourself: