NAME

       puttygen - public-key generator for the PuTTY tools

SYNOPSIS

       puttygen ( keyfile | -t keytype [ -b bits ] )
                [ -C new-comment ] [ -P ] [ -q ]
                [ -O output-type | -l | -L | -p ]
                [ -o output-file ]

DESCRIPTION

       puttygen is a tool to generate and manipulate SSH public and private key pairs. It is part
       of the PuTTY suite, although it can also interoperate with the private key formats used by
       some other SSH clients.

       When you run puttygen, it does three things. Firstly, it either loads an existing key file
       (if you specified keyfile), or generates a new key (if you specified  keytype).  Then,  it
       optionally  makes  modifications  to the key (changing the comment and/or the passphrase);
       finally, it outputs the key, or some information about the key, to a file.

       All three of these phases are  controlled  by  the  options  described  in  the  following
       section.

OPTIONS

       In  the  first phase, puttygen either loads or generates a key. Note that generating a key
       requires random data (from /dev/random), which can cause puttygen to pause,  possibly  for
       some time if your system does not have much randomness available.

       The options to control this phase are:

       keyfile
              Specify  a  private  key file to be loaded. This private key file can be in the (de
              facto standard) SSH-1 key format, or in PuTTY's SSH-2 key format, or in  either  of
              the SSH-2 private key formats used by OpenSSH and ssh.com's implementation.

       -t keytype
              Specify  a  type of key to generate. The acceptable values here are rsa and dsa (to
              generate SSH-2 keys), and rsa1 (to generate SSH-1 keys).

       -b bits
              Specify the size of the key to generate, in bits. Default is 2048.

       -q     Suppress the progress display when generating a new key.

       In the second phase, puttygen optionally alters properties of the key  it  has  loaded  or
       generated. The options to control this are:

       -C new-comment
              Specify  a  comment string to describe the key. This comment string will be used by
              PuTTY to identify the key to you (when asking you  to  enter  the  passphrase,  for
              example, so that you know which passphrase to type).

       -P     Indicate  that  you want to change the key's passphrase. This is automatic when you
              are generating a new key, but not when you are modifying an existing key.

       In the third phase, puttygen saves the key or information about it. The options to control
       this are:

       -O output-type
              Specify the type of output you want puttygen to produce. Acceptable options are:

              private
                     Save  the  private  key in a format usable by PuTTY. This will either be the
                     standard SSH-1 key format, or PuTTY's own SSH-2 key format.

              public Save the public key only. For SSH-1 keys, the  standard  public  key  format
                     will  be used (`1024 37 5698745...'). For SSH-2 keys, the public key will be
                     output in the format specified by RFC 4716, which is a multi-line text  file
                     beginning with the line `---- BEGIN SSH2 PUBLIC KEY ----'.

              public-openssh
                     Save  the  public  key  only, in a format usable by OpenSSH. For SSH-1 keys,
                     this output format behaves identically to public. For SSH-2 keys, the public
                     key  will  be output in the OpenSSH format, which is a single line (`ssh-rsa
                     AAAAB3NzaC1yc2...').

              fingerprint
                     Print the fingerprint of the public key. All fingerprinting  algorithms  are
                     believed compatible with OpenSSH.

              private-openssh
                     Save  an SSH-2 private key in OpenSSH's format. This option is not permitted
                     for SSH-1 keys.

              private-sshcom
                     Save an SSH-2 private key in ssh.com's format. This option is not  permitted
                     for SSH-1 keys.

              If no output type is specified, the default is private.

       -o output-file
              Specify  the  file  where  puttygen  should write its output. If this option is not
              specified, puttygen will assume you want to overwrite  the  original  file  if  the
              input  and  output  file types are the same (changing a comment or passphrase), and
              will assume you want to output to stdout if you are asking  for  a  public  key  or
              fingerprint. Otherwise, the -o option is required.

       -l     Synonym for `-O fingerprint'.

       -L     Synonym for `-O public-openssh'.

       -p     Synonym for `-O public'.

       The  following options do not run PuTTYgen as normal, but print informational messages and
       then quit:

       -h, --help
              Display a message summarizing the available options.

       -V, --version
              Display the version of PuTTYgen.

       --pgpfp
              Display the fingerprints of the PuTTY PGP Master Keys,  to  aid  in  verifying  new
              files released by the PuTTY team.

EXAMPLES

       To  generate an SSH-2 RSA key pair and save it in PuTTY's own format (you will be prompted
       for the passphrase):

       puttygen -t rsa -C "my home key" -o mykey.ppk

       To generate a larger (4096-bit) key:

       puttygen -t rsa -b 4096 -C "my home key" -o mykey.ppk

       To change the passphrase on a key (you will be prompted for the old and new passphrases):

       puttygen -P mykey.ppk

       To change the comment on a key:

       puttygen -C "new comment" mykey.ppk

       To convert a key into OpenSSH's private key format:

       puttygen mykey.ppk -O private-openssh -o my-openssh-key

       To convert a key from another format (puttygen will automatically  detect  the  input  key
       type):

       puttygen my-ssh.com-key -o mykey.ppk

       To  display  the fingerprint of a key (some key types require a passphrase to extract even
       this much information):

       puttygen -l mykey.ppk

       To add the OpenSSH-format public half of a key to your authorised keys file:

       puttygen -L mykey.ppk >> $HOME/.ssh/authorized_keys

BUGS

       There's currently no way to supply passphrases in batch mode, or even just to specify that
       you don't want a passphrase at all.