Differences between version 7 and predecessor to the previous major change of ssh-keygen(1).
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| Newer page: | version 7 | Last edited on Friday, September 19, 2003 4:07:50 pm | by MichaelHart | Revert |
| Older page: | version 1 | Last edited on Monday, June 3, 2002 11:56:10 pm | by perry | Revert |
@@ -3,8 +3,10 @@
ssh-keygen - authentication key generation, management and
conversion
+
+
__SYNOPSIS__
ssh-keygen [[-q] [[-b bits] [[-t type] [[-N new_passphrase] [[-C
@@ -37,8 +39,10 @@
ssh-keygen -D reader
ssh-keygen -U reader [[-f input_keyfile]
+
+
__DESCRIPTION__
ssh-keygen generates, manages and converts authentication
@@ -50,57 +54,52 @@
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 administrator may use this to generate host keys, as seen in /etc/rc.
-Normally this program generates the key and asks for a file
-
-
-
-
-
-
-
-pro-
-vides
very bad passphrases). The passphrase can be changed
-
+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. Good passphrases are 10-30 characters long and are not simple sentences or otherwise easily guessable (English prose has only 1-2 bits of entropy per character, and provides
very bad passphrases). The passphrase can be changed later by using the -p option.
-There is no way to recover a lost passphrase. If the
-
-
-
+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
-
-what-
-ever
is useful. The comment is initialized to ``user@host''
-
-
+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 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
-
+After a key is generated, instructions below detail where the keys should be placed to be activated.
-The options are as follows:
- -b bits
+''
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 consid-ered sufficient, and key sizes above that no longer improve security but make things slower. The defaultis 1024 bits.
-Specifies the number of bits in the key to create.Minimum is 512 bits. Generally 1024 bits is consid-ered sufficient, and key sizes above that no longerimprove security but make things slower. The defaultis 1024 bits.
-cRequests
changing the comment in the private and pub-lic
key files. This operation is only supported forRSA1
keys. The program will prompt for the file con-taining
the private keys, for the passphrase if thekey
has one, and for the new comment.-eThis option will read a private or public OpenSSH keyfile and print the key in a SECSH Public Key FileFormat to stdout. This option allows exporting keysfor use by several commercial SSH implementations.-f filenameSpecifies the filename of the key file.-iThis option will read an unencrypted private (or pub-lic) key file in SSH2-compatible format and print anOpenSSH compatible private (or public) key to stdout.ssh-keygen also reads the SECSH Public Key FileFormat. This option allows importing keys from sev-eral commercial SSH implementations.-lShow fingerprint of specified public key file. Pri-vate RSA1 keys are also supported. For RSA and DSAkeys ssh-keygen tries to find the matching public keyfile and prints its fingerprint.-pRequests changing the passphrase of a private keyfile instead of creating a new private key. The pro-gram will prompt for the file containing the privatekey, for the old passphrase, and twice for the newpassphrase.-qSilence ssh-keygen. Used by /etc/rc when creating a new key
.
+-c
+Requests
changing the comment in the private and public
key files. This operation is only supported for RSA1
keys. The program 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 keyfile and print the key in a SECSH Public Key !FileFormat to stdout. This option allows exporting keys for use by several commercial SSH implementations.
--y
-This option will read a private OpenSSH format
file and
-print an OpenSSH public key to stdout
.
+-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 !FileFormat. 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 keyfile and prints its fingerprint.
+
+-p
+Requests changing the passphrase of a private keyfile instead of creating a new private key. The program will prompt for the file containing the privatekey, for the old passphrase, and twice for the newpassphrase.
+
+-q
+Silence ssh-keygen. Used by /etc/rc when creating a new key.
-t type
-Specifies the type of the key to create. The possi- ble
-
-
-
+Specifies the type of the key to create. The possible
values are ``rsa1'' for protocol version 1 and ``rsa'' or ``dsa'' for protocol version 2. The default is ``rsa1''.
+-y
+This option will read a private OpenSSH format file and
+print an OpenSSH public key to stdout.
-B
Show the bubblebabble digest of specified private or public
key file.
@@ -204,6 +203,6 @@
ssh(1), ssh-add(1), ssh-agent(1),
sshd(8)
-
J. Galbraith and R. Thayer,'' SECSH Public Key FileFormat'', draft-ietf-secsh-publickeyfile-01.txt, March2001, work in progress material.BSD September 25, 1999 1
+J. Galbraith and R. Thayer,'' SECSH Public Key !
FileFormat'', draft-ietf-secsh-publickeyfile-01.txt, March2001, work in progress material.BSD September 25, 1999 1
----
