Links regarding OPENSSH key format

nice read: https://coolaj86.com/articles/the-openssh-private-key-format/

See discussion: https://bugs.eclipse.org/bugs/show_bug.cgi?id=541703

implementation of bcrypt_pbkdf: https://github.com/kruton/jbcrypt/blob/master/src/main/java/org/mindrot/jbcrypt/BCrypt.java