SSH-KEYGEN(1)           System General Commands Manual           SSH-KEYGEN(1)NAME     ssh-keygen - authentication key generation, management and conversionSYNOPSIS     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 -D reader     ssh-keygen -U reader [-f input_keyfile]DESCRIPTION     ssh-keygen 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.  Additionally, the system adminM--     istrator may use this to generate host keys, as seen in /etc/rc.     Normally 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 ``.pub'' appended.  The program also asks for a passphrase.  The     passphrase may be empty to indicate no passphrase (host keys must have an     empty passphrase), or it may be a string of arbitrary length.  A     passphrase is similar to a password, except it can be a phrase with a     series of words, punctuation, numbers, whitespace, or any string of charM--     acters you want.  Good passphrases are 10-30 characters long, are not     simple sentences or otherwise easily guessable (English prose has only     1-2 bits of entropy per character, and provides very bad passphrases),     and contain a mix of upper and lowercase letters, numbers, and non-     alphanumeric characters.  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, a new key must be generated and copied to the corresponding     public key to other machines.     For RSA1 keys, 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 initialM--     ized 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 the keys should     be placed to be activated.     The options are as follows:     -b bits             Specifies the number of bits in the key to create.  Minimum is             512 bits.  Generally 1024 bits is considered sufficient, and key             sizes above that no longer improve security but make things             slower.  The default is 1024 bits.     -c      Requests changing the comment in the private and public key             files.  This operation is only supported for RSA1 keys.  The proM--             gram will prompt for the file containing the private keys, for             the passphrase if the key has one, and for the new comment.     -e      This option will read a private or public OpenSSH key file and             print the key in a `SECSH Public Key File Format' to stdout.             This option allows exporting keys for use by several commercial             SSH implementations.     -f filename             Specifies the filename of the key file.     -i      This option will read an unencrypted private (or public) key file             in SSH2-compatible format and print an OpenSSH compatible private             (or public) key to stdout.  ssh-keygen also reads the `SECSH             Public Key File Format'.  This option allows importing keys from             several commercial SSH implementations.     -l      Show fingerprint of specified public key file.  Private RSA1 keys             are also supported.  For RSA and DSA keys ssh-keygen tries to             find the matching public key file and prints its fingerprint.     -p      Requests changing the passphrase of a private key file instead of             creating a new private key.  The program will prompt for the file             containing the private key, for the old passphrase, and twice for             the new passphrase.     -q      Silence ssh-keygen.  Used by /etc/rc when creating a new key.     -y      This option will read a private OpenSSH format file and print an             OpenSSH public key to stdout.     -t type             Specifies the type of the key to create.  The possible values are             ``rsa1'' for protocol version 1 and ``rsa'' or ``dsa'' for protoM--             col version 2.     -B      Show the bubblebabble digest of specified private or public key             file.     -C comment             Provides the new comment.     -D reader             Download the RSA public key stored in the smartcard in reader.     -N new_passphrase             Provides the new passphrase.     -P passphrase             Provides the (old) passphrase.     -U reader             Upload an existing RSA private key into the smartcard in reader.FILES     $HOME/.ssh/identity             Contains the protocol version 1 RSA authentication identity of             the user.  This file should not be readable by anyone but the             user.  It is possible to specify a passphrase when generating the             key; that passphrase will be 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.  ssh(1) will read this file when a login attempt is made.     $HOME/.ssh/identity.pub             Contains the protocol version 1 RSA public key for authenticaM--             tion.  The contents of this file should be added to             $HOME/.ssh/authorized_keys on all machines where the user wishes             to log in using RSA authentication.  There is no need to keep the             contents of this file secret.     $HOME/.ssh/id_dsa             Contains the protocol version 2 DSA authentication identity of             the user.  This file should not be readable by anyone but the             user.  It is possible to specify a passphrase when generating the             key; that passphrase will be 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.  ssh(1) will read this file when a login attempt is made.     $HOME/.ssh/id_dsa.pub             Contains the protocol version 2 DSA public key for authenticaM--             tion.  The contents of this file should be added to             $HOME/.ssh/authorized_keys on all machines where the user wishes             to log in using public key authentication.  There is no need to             keep the contents of this file secret.     $HOME/.ssh/id_rsa             Contains the protocol version 2 RSA authentication identity of             the user.  This file should not be readable by anyone but the             user.  It is possible to specify a passphrase when generating the             key; that passphrase will be 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.  ssh(1) will read this file when a login attempt is made.     $HOME/.ssh/id_rsa.pub             Contains the protocol version 2 RSA public key for authenticaM--             tion.  The contents of this file should be added to             $HOME/.ssh/authorized_keys on all machines where the user wishes             to log in using public key authentication.  There is no need to             keep the contents of this file secret.AUTHORS     OpenSSH is a derivative of the original and free ssh 1.2.12 release by     Tatu Ylonen.  Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo     de Raadt and Dug Song removed many bugs, re-added newer features and creM--     ated OpenSSH.  Markus Friedl contributed the support for SSH protocol     versions 1.5 and 2.0.SEE ALSO     ssh(1), ssh-add(1), ssh-agent(1), sshd(8)     J. Galbraith and R. Thayer, SECSH Public Key File Format, draft-ietf-     secsh-publickeyfile-01.txt, March 2001, work in progress material.BSD                           September 25, 1999                           BSD