--- ssh-keygen.0 Tue Jan 16 13:25:11 2007 +++ ssh-keygen.0.new Tue Jan 16 13:25:15 2007 @@ -1,233 +1,268 @@ User Commands ssh-keygen(1) NAME ssh-keygen - authentication key generation SYNOPSIS ssh-keygen [-q] [-b bits ] -t type [-N new_passphrase] [-C comment] [-f output_keyfile] ssh-keygen -p [-P old_passphrase] [-N new_passphrase] [-f keyfile] ssh-keygen -i [-f input_keyfile] ssh-keygen -e [-f input_keyfile] ssh-keygen -y [-f input_keyfile] ssh-keygen -c [-P passphrase] [-C comment] [-f keyfile] ssh-keygen -l [-f input_keyfile] ssh-keygen -B [-f input_keyfile] + ssh-keygen -F hostname [-f known_hosts_file] + + ssh-keygen -H [-f known_hosts_file] + + ssh-keygen -R hostname [-f known_hosts_file] + DESCRIPTION The ssh-keygen utility generates, manages, and converts authentication keys for ssh(1). ssh-keygen can create RSA keys for use by SSH protocol version 1 and RSA or DSA keys for use by SSH protocol version 2. The type of key to be generated is specified with the -t option. Normally, each user wishing to use SSH with RSA or DSA authentication runs this once to create the authentication key in $HOME/.ssh/identity, $HOME/.ssh/id_dsa, or $HOME/.ssh/id_rsa. The system administrator can also use this to generate host keys.. Ordinarily, this program generates the key and asks for a file in which to store the private key. The public key is stored in a file with the same name but with the ``.pub'' extension appended. The program also asks for a passphrase. The passphrase can be empty to indicate no passphrase (host keys must have empty passphrases), or it can be a string of arbitrary length. Good passphrases are 10-30 characters long, are not simple sentences or otherwise easy to guess, and contain a mix of uppercase and lowercase letters, numbers, and non-alphanumeric characters. (English prose has only 1-2 bits of entropy per word and provides very poor passphrases.) The passphrase can be changed later by using the -p option. There is no way to recover a lost passphrase. If the passphrase is lost or forgotten, you have to generate a new SunOS 5.10 Last change: 9 Nov 2004 1 User Commands ssh-keygen(1) key and copy the corresponding public key to other machines. For RSA, there is also a comment field in the key file that is only for convenience to the user to help identify the key. The comment can tell what the key is for, or whatever is useful. The comment is initialized to ``user@host'' when the key is created, but can be changed using the -c option. After a key is generated, instructions below detail where to place the keys to activate them. OPTIONS The following options are supported: -b bits Specifies the number of bits in the key to create. The minimum number is 512 bits. Generally, 1024 bits is considered sufficient. Key sizes above that no longer improve secu- rity but make things slower. The default is 1024 bits. -B Shows the bubblebabble digest of the specified private or public key file. -c Requests changing the comment in the private and public key files. The program prompts for the file con- taining the private keys, for the passphrase if the key has one, and for the new comment. This option only applies to rsa1 (SSHv1) keys. -C comment Provides the new comment. -e This option reads a private or pub- lic OpenSSH key file and prints the key in a "SECSH" Public Key File Format to stdout. This option allows exporting keys for use by several other SSH implementations. SunOS 5.10 Last change: 9 Nov 2004 2 User Commands ssh-keygen(1) -f Specifies the filename of the key file. + -F hostname Search for the specified hostname in + a known_hosts file, listing any + occurrences found. This option is + useful to find hashed host names or + addresses and may also be used in + conjunction with the -H option to + print found keys in a hashed format. + + -H Hash a known_hosts file. This + replaces all hostnames and ad- + dresses with hashed representations + within the specified file; the + original content is moved to a file + with a .old suffix. These hashes may + be used normally by ssh and sshd, + but they do not reveal identifying + information should the file's + contents be disclosed. This option + will not modify existing hashed + hostnames and is therefore safe to + use on files that mix hashed and + non- hashed names. + -i This option reads an unencrypted private (or public) key file in SSH2-compatible format and prints an OpenSSH compatible private (or pub- lic) key to stdout. ssh-keygen also reads the "SECSH" Public Key File Format. This option allows import- ing keys from several other SSH implementations. -l Shows the fingerprint of the speci- fied private or public key file. -N new_passphrase Provides the new passphrase. -p Requests changing the passphrase of a private key file instead of creat- ing a new private key. The program prompts for the file containing the private key, for the old passphrase, and prompts twice for the new passphrase. -P passphrase Provides the (old) passphrase. -q Silences ssh-keygen. + -R hostname Removes all keys belonging to + hostname from a known_hosts file. + This option is useful to delete + hashed hosts (see the -H option + above). + -t type Specifies the algorithm used for the key, where type is one of rsa, dsa, and rsa1. Type rsa1 is used only for the SSHv1 protocol. SunOS 5.10 Last change: 9 Nov 2004 3 User Commands ssh-keygen(1) -x Obsolete. Replaced by the -e option. -X Obsolete. Replaced by the -i option. -y This option reads a private OpenSSH format file and prints an OpenSSH public key to stdout. EXIT STATUS The following exit values are returned: 0 Successful completion. 1 An error occurred. FILES $HOME/.ssh/identity This file contains the RSA private key for the SSHv1 protocol. This file should not be readable by anyone but the user. It is possible to specify a passphrase when generating the key; that passphrase is used to encrypt the private part of this file using 3DES. This file is not automatically accessed by ssh-keygen, but it is offered as the default file for the private key. sshd(1M) reads this file when a login attempt is made. $HOME/.ssh/identity.pub This file contains the RSA public key for the SSHv1 pro- tocol. The contents of this file should be added to $HOME/.ssh/authorized_keys on all machines where you wish to log in using RSA authentication. There is no need to keep the contents of this file secret. $HOME/.ssh/id_dsa $HOME/.ssh/id_rsa SunOS 5.10 Last change: 9 Nov 2004 4 User Commands ssh-keygen(1) These files contain, respectively, the DSA or RSA private key for the SSHv2 protocol. These files should not be readable by anyone but the user. It is possible to specify a passphrase when generating the key; that passphrase is used to encrypt the private part of the file using 3DES. Neither of these files is automatically accessed by ssh-keygen but is offered as the default file for the private key. sshd(1M) reads this file when a login attempt is made. $HOME/.ssh/id_dsa.pub $HOME/.ssh/id_rsa.pub These files contain, respectively, the DSA or RSA public key for the SSHv2 protocol. The contents of these files should be added, respectively, to $HOME/.ssh/authorized_keys on all machines where you wish to log in using DSA or RSA authentication. There is no need to keep the contents of these files secret. ATTRIBUTES See attributes(5) for descriptions of the following attri- butes: ____________________________________________________________ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | |_____________________________|_____________________________| | Availability | SUNWsshcu | |_____________________________|_____________________________| | Interface Stability | Evolving | |_____________________________|_____________________________| SEE ALSO ssh(1), ssh-add(1), ssh-agent(1), sshd(1M), attributes(5) To view license terms, attribution, and copyright for OpenSSH, the default path is /var/sadm/pkg/SUNWsshdr/install/copyright. If the Solaris operating environment has been installed anywhere other than the default, modify the given path to access the file at the installed location. SunOS 5.10 Last change: 9 Nov 2004 5