1SSH-KEYSIGN(8) BSD System Manager's Manual SSH-KEYSIGN(8)
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4 ssh-keysign — ssh helper program for host-based authentication
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7 ssh-keysign
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10 ssh-keysign is used by ssh(1) to access the local host keys and generate
11 the digital signature required during host-based authentication with SSH
12 protocol version 2.
13 ssh-keysign is disabled by default and can only be enabled in the global
15 client configuration file /etc/ssh/ssh_config by setting EnableSSHKeysign
16 to “yes”.
17 ssh-keysign is not intended to be invoked by the user, but from ssh(1).
19 See ssh(1) and sshd(8) for more information about host-based authentica‐
20 tion.
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23 /etc/ssh/ssh_config
24 Controls whether ssh-keysign is enabled.
25 /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_ecdsa_key,
27 /etc/ssh/ssh_host_rsa_key
28 These files contain the private parts of the host keys used to
29 generate the digital signature. They should be owned by root,
30 readable only by root, and not accessible to others. Since they
31 are readable only by root, ssh-keysign must be set-uid root if
32 host-based authentication is used.
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35 SSH_USE_STRONG_RNG
36 The reseeding of the OpenSSL random generator is usually done
37 from /dev/urandom. If the SSH_USE_STRONG_RNG environment vari‐
38 able is set to value other than 0 the OpenSSL random generator is
39 reseeded from /dev/random. The number of bytes read is defined
40 by the SSH_USE_STRONG_RNG value. Minimum is 14 bytes. This set‐
41 ting is not recommended on the computers without the hardware
42 random generator because insufficient entropy causes the connec‐
43 tion to be blocked until enough entropy is available.
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46 ssh(1), ssh-keygen(1), ssh_config(5), sshd(8)
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49 ssh-keysign first appeared in OpenBSD 3.2.
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52 Markus Friedl <markus@openbsd.org>
53BSD June 21, 2019 BSD