Keyfile

A key file ( engl. " keyfile ") is a file that contains one or more cryptographic keys. Key files are used for password management for encryption and decryption, or for storing license keys.

Pros and Cons

The key file is an alternative to manually entering a password. This will allow significantly longer and more complex keys can be used and it no longer exists the danger of forgetting the password. However, the key file is lost due to data loss. The attack scenario with a password consists of Spying ( for example, by a keylogger ) or guessing ( for example, a dictionary attack ); a key file, however, is to protect against unauthorized access, so it is not copied. Often key files may also be encrypted with a master password.

Practice

Key files play, for example, at a public-key infrastructure a role. For different applications, and key species, there are different standards as a key file is structured, for example RFC 4716 Secure Shell (SSH). In some applications, for example TrueCrypt, it is also possible to use an arbitrary file as a key, and so the presence of a key to conceal ( steganography ).

Examples

• When an SSH public key in the authorized_keys file and private key are stored in the file called id_dsa. The key file with the public key is distributed, while the private key file must be secured against unauthorized access.
• With PGP key files are called public key and key rings, these can be published on key servers. The private key file is encrypted protected by a passphrase.