ssh-keygen(1)							   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 pro-
       tocol 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/iden-
       tity, $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.) If a passphrase is set, it must be at
       least 4 characters long.

       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 key and  copy  the  corre-
       sponding 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 security 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  containing  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 public OpenSSH key file and prints the key in a "SECSH" Public Key File Format to std-
			    out. This option allows exporting keys for use by several other SSH implementations.

       -f		    Specifies the filename of the key file.

       -F		    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 can 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 host names and addresses 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  does  not  modify
			    existing hashed host names 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 compati-
			    ble private (or public) key to stdout. ssh-keygen also reads the "SECSH" Public Key File Format.  This  option  allows
			    importing keys from several other SSH implementations.

       -l		    Shows the fingerprint of the specified private or public key file.

       -N new_passphrase    Provides the new passphrase.

       -p		    Requests  changing the passphrase of a private key file instead of creating 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.

       -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.

       -R hostname	    Removes all keys belonging to hostname from a known_hosts file. This option is useful to delete hashed hosts. See -H.

       -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 protocol. 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	  These files contain, respectively, the DSA or RSA private key for the SSHv2 protocol. These files should not	be
       $HOME/.ssh/id_rsa	  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	  These files contain, respectively, the DSA or RSA public key for the SSHv2 protocol. The contents of these files
       $HOME/.ssh/id_rsa.pub	  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 attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWsshcu 		   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Committed 		   |
       +-----------------------------+-----------------------------+

SEE ALSO

       ssh(1), ssh-add(1), ssh-agent(1), sshd(1M), attributes(5)

SunOS 5.11							    17 Feb 2009 						     ssh-keygen(1)