Xgu.ru теперь в Контакте  — приходите и подключайтесь.
Пока мы работаем над следующими видео, вы можете подключиться в Контакте. Познакомимся и обсудим новые страницы и ролики.

Vk-big.pngYoutube-big.jpeg

man/orig/ssh-keygen(1)

Материал из Xgu.ru

Перейти к: навигация, поиск

ssh-keygen • man/ssh-keygen • man/orig/ssh-keygen • Пример использования ssh-keygen


SSH-KEYGEN(1) BSD General Commands Manual SSH-KEYGEN(1)

Содержание

[править] NAME

    ssh-keygen - authentication key generation, management and conversion

[править] 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 -D pkcs11
    ssh-keygen -F hostname [-f known_hosts_file] [-l]
    ssh-keygen -H [-f known_hosts_file]
    ssh-keygen -R hostname [-f known_hosts_file]
    ssh-keygen -r hostname [-f input_keyfile] [-g]
    ssh-keygen -G output_file [-v] [-b bits] [-M memory] [-S start_point]
    ssh-keygen -T output_file -f input_file [-v] [-a num_trials]
               [-W generator]
    ssh-keygen [-n] [-D smartcard]
    ssh-keygen -s ca_key -I certificate_identity [-h] [-n principals]
               [-O option] [-V validity_interval] [-z serial_number] file ...
    ssh-keygen -L [-f input_keyfile]

[править] 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.  If invoked without any
    arguments, ssh-keygen will generate an RSA key for use in SSH protocol 2
    connections.
    ssh-keygen is also used to generate groups for use in Diffie-Hellman
    group exchange (DH-GEX).  See the MODULI GENERATION section for details.
    Normally each user wishing to use SSH with RSA or DSA authentication runs
    this once to create the authentication key in ~/.ssh/identity,
    ~/.ssh/id_dsa or ~/.ssh/id_rsa.  Additionally, the system administrator
    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 char-
    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 initial-
    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:
    -a trials
            Specifies the number of primality tests to perform when screening
            DH-GEX candidates using the -T command.
    -B      Show the bubblebabble digest of specified private or public key
            file.
    -b bits
            Specifies the number of bits in the key to create.  For RSA keys,
            the minimum size is 768 bits and the default is 2048 bits.  Gen-
            erally, 2048 bits is considered sufficient.  DSA keys must be
            exactly 1024 bits as specified by FIPS 186-2.
    -C comment
            Provides a new comment.
    -c      Requests changing the comment in the private and public key
            files.  This operation is only supported for RSA1 keys.  The pro-
            gram will prompt for the file containing the private keys, for
            the passphrase if the key has one, and for the new comment.
    -D pkcs11
            Download the RSA public keys stored in the pkcs11 provider.
    -e      This option will read a private or public OpenSSH key file and
            print the key in RFC 4716 SSH Public Key File Format to stdout.
            This option allows exporting keys for use by several commercial
            SSH implementations.
    -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.
    -f filename
            Specifies the filename of the key file.
    -G output_file
            Generate candidate primes for DH-GEX.  These primes must be
            screened for safety (using the -T option) before use.
    -g      Use generic DNS format when printing fingerprint resource records
            using the -r command.
    -H      Hash a known_hosts file.  This replaces all hostnames 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 will not modify existing hashed hostnames
            and is therefore safe to use on files that mix hashed and non-
            hashed names.
    -h      When signing a key, create a host certificate instead of a user
            certificate.  Please see the CERTIFICATES section for details.
    -I      Specify the key identity when signing a public key.  Please see
            the CERTIFICATES section for details.
    -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 RFC 4716
            SSH Public Key File Format.  This option allows importing keys
            from several commercial SSH implementations.
    -L      Prints the contents of a certificate.
    -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.  If
            combined with -v, an ASCII art representation of the key is sup-
            plied with the fingerprint.
    -M memory
            Specify the amount of memory to use (in megabytes) when generat-
            ing candidate moduli for DH-GEX.
    -n      Extract the public key from smartcard.
    -N new_passphrase
            Provides the new passphrase.
    -n principals
            Specify one or more principals (user or host names) to be
            included in a certificate when signing a key.  Multiple princi-
            pals may be specified, separated by commas.  Please see the
            CERTIFICATES section for details.
    -O option
            Specify a certificate option when signing a key.  This option may
            be specified multiple times.  Please see the CERTIFICATES section
            for details.  The options that are valid for user certificates
            are:
            no-x11-forwarding
                    Disable X11 forwarding. (permitted by default)
            no-agent-forwarding
                    Disable ssh-agent(1) forwarding. (permitted by default)
            no-port-forwarding
                    Disable port forwarding. (permitted by default)
            no-pty  Disable PTY allocation. (permitted by default)
            no-user-rc
                    Disable execution of ~/.ssh/rc by sshd(8).  (permitted by
                    default)
            clear   Clear all enabled permissions.  This is useful for clear-
                    ing the default set of permissions so permissions may be
                    added individually.
            permit-x11-forwarding
                    Allows X11 forwarding.
            permit-agent-forwarding
                    Allows ssh-agent(1) forwarding.
            permit-port-forwarding
                    Allows port forwarding.
            permit-pty
                    Allows PTY allocation.
            permit-user-rc
                    Allows execution of ~/.ssh/rc by sshd(8).
            force-command=command
                    Forces the execution of command instead of any shell or
                    command specified by the user when the certificate is
                    used for authentication.
            source-address=address_list
                    Restrict the source addresses from which the certificate
                    is considered valid from.  The address_list is a comma-
                    separated list of one or more address/netmask pairs in
                    CIDR format.
            At present, no options are valid for host keys.
    -P passphrase
            Provides the (old) passphrase.
    -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.
    -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).
    -r hostname
            Print the SSHFP fingerprint resource record named hostname for
            the specified public key file.
    -S start
            Specify start point (in hex) when generating candidate moduli for
            DH-GEX.
    -s ca_key
            Certify (sign) a public key using the specified CA key.  Please
            see the CERTIFICATES section for details.
    -T output_file
            Test DH group exchange candidate primes (generated using the -G
            option) for safety.
    -t type
            Specifies the type of key to create.  The possible values are
            “rsa1” for protocol version 1 and “rsa” or “dsa” for protocol
            version 2.
    -V validity_interval
            Specify a validity interval when signing a certificate.  A valid-
            ity interval may consist of a single time, indicating that the
            certificate is valid beginning now and expiring at that time, or
            may consist of two times separated by a colon to indicate an
            explicit time interval.  The start time may be specified as a
            date in YYYYMMDD format, a time in YYYYMMDDHHMMSS format or a
            relative time (to the current time) consisting of a minus sign
            followed by a relative time in the format described in the TIME
            FORMATS section of ssh_config(5).  The end time may be specified
            as a YYYYMMDD date, a YYYYMMDDHHMMSS time or a relative time
            starting with a plus character.
            For example: “+52w1d” (valid from now to 52 weeks and one day
            from now), “-4w:+4w” (valid from four weeks ago to four weeks
            from now), “20100101123000:20110101123000” (valid from 12:30 PM,
            January 1st, 2010 to 12:30 PM, January 1st, 2011), “-1d:20110101”
            (valid from yesterday to midnight, January 1st, 2011).
    -v      Verbose mode.  Causes ssh-keygen to print debugging messages
            about its progress.  This is helpful for debugging moduli genera-
            tion.  Multiple -v options increase the verbosity.  The maximum
            is 3.
    -W generator
            Specify desired generator when testing candidate moduli for DH-
            GEX.
    -y      This option will read a private OpenSSH format file and print an
            OpenSSH public key to stdout.
    -z serial_number
            Specifies a serial number to be embedded in the certificate to
            distinguish this certificate from others from the same CA.  The
            default serial number is zero.

[править] MODULI GENERATION

    ssh-keygen may be used to generate groups for the Diffie-Hellman Group
    Exchange (DH-GEX) protocol.  Generating these groups is a two-step pro-
    cess: first, candidate primes are generated using a fast, but memory
    intensive process.  These candidate primes are then tested for suitabil-
    ity (a CPU-intensive process).
    Generation of primes is performed using the -G option.  The desired
    length of the primes may be specified by the -b option.  For example:
          # ssh-keygen -G moduli-2048.candidates -b 2048
    By default, the search for primes begins at a random point in the desired
    length range.  This may be overridden using the -S option, which speci-
    fies a different start point (in hex).
    Once a set of candidates have been generated, they must be tested for
    suitability.  This may be performed using the -T option.  In this mode
    ssh-keygen will read candidates from standard input (or a file specified
    using the -f option).  For example:
          # ssh-keygen -T moduli-2048 -f moduli-2048.candidates
    By default, each candidate will be subjected to 100 primality tests.
    This may be overridden using the -a option.  The DH generator value will
    be chosen automatically for the prime under consideration.  If a specific
    generator is desired, it may be requested using the -W option.  Valid
    generator values are 2, 3, and 5.
    Screened DH groups may be installed in /etc/ssh/moduli.  It is important
    that this file contains moduli of a range of bit lengths and that both
    ends of a connection share common moduli.

[править] CERTIFICATES

    ssh-keygen supports signing of keys to produce certificates that may be
    used for user or host authentication.  Certificates consist of a public
    key, some identity information, zero or more principal (user or host)
    names and a set of options that are signed by a Certification Authority
    (CA) key.  Clients or servers may then trust only the CA key and verify
    its signature on a certificate rather than trusting many user/host keys.
    Note that OpenSSH certificates are a different, and much simpler, format
    to the X.509 certificates used in ssl(8).
    ssh-keygen supports two types of certificates: user and host.  User cer-
    tificates authenticate users to servers, whereas host certificates
    authenticate server hosts to users. To generate a user certificate:
          $ ssh-keygen -s /path/to/ca_key -I key_id /path/to/user_key.pub
    The resultant certificate will be placed in /path/to/user_key-cert.pub.
    A host certificate requires the -h option:
          $ ssh-keygen -s /path/to/ca_key -I key_id -h /path/to/host_key.pub
    The host certificate will be output to /path/to/host_key-cert.pub.  In
    both cases, key_id is a "key identifier" that is logged by the server
    when the certificate is used for authentication.
    Certificates may be limited to be valid for a set of principal
    (user/host) names.  By default, generated certificates are valid for all
    users or hosts.  To generate a certificate for a specified set of princi-
    pals:
          $ ssh-keygen -s ca_key -I key_id -n user1,user2 user_key.pub
          $ ssh-keygen -s ca_key -I key_id -h -n host.domain user_key.pub
    Additional limitations on the validity and use of user certificates may
    be specified through certificate options.  A certificate option may dis-
    able features of the SSH session, may be valid only when presented from
    particular source addresses or may force the use of a specific command.
    For a list of valid certificate options, see the documentation for the -O
    option above.
    Finally, certificates may be defined with a validity lifetime.  The -V
    option allows specification of certificate start and end times.  A cer-
    tificate that is presented at a time outside this range will not be con-
    sidered valid.  By default, certificates have a maximum validity inter-
    val.
    For certificates to be used for user or host authentication, the CA pub-
    lic key must be trusted by sshd(8) or ssh(1).  Please refer to those man-
    ual pages for details.

[править] FILES

    ~/.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.
    ~/.ssh/identity.pub
            Contains the protocol version 1 RSA public key for authentica-
            tion.  The contents of this file should be added to
            ~/.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.
    ~/.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.
    ~/.ssh/id_dsa.pub
            Contains the protocol version 2 DSA public key for authentica-
            tion.  The contents of this file should be added to
            ~/.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.
    ~/.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.
    ~/.ssh/id_rsa.pub
            Contains the protocol version 2 RSA public key for authentica-
            tion.  The contents of this file should be added to
            ~/.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.
    /etc/ssh/moduli
            Contains Diffie-Hellman groups used for DH-GEX.  The file format
            is described in moduli(5).

[править] ENVIRONMENT

    SSH_USE_STRONG_RNG
            The reseeding of the OpenSSL random generator is usually done
            from /dev/urandom.  If the SSH_USE_STRONG_RNG environment vari-
            able is set to value other than 0 the OpenSSL random generator is
            reseeded from /dev/random.  The number of bytes read is defined
            by the SSH_USE_STRONG_RNG value.  Minimum is 14 bytes.  This set-
            ting is not recommended on the computers without the hardware
            random generator because insufficient entropy causes the connec-
            tion to be blocked until enough entropy is available.

[править] SEE ALSO


    The Secure Shell (SSH) Public Key File Format, RFC 4716, 2006.

[править] 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 cre-
    ated OpenSSH.  Markus Friedl contributed the support for SSH protocol
    versions 1.5 and 2.0.

BSD October 21, 2014 BSD