sshng2john is a tool used to convert SSH private keys in OpenSSH format to a format that can be cracked using password cracking tools like John the Ripper. This can finally result in cracking the password of the private key.
Command Reference:
Private SSH key: id_rsa
sshng2john.py id_rsa
john --wordlist=/opt/wordlists/rockyou.txt sshkey.john