1IPSEC_RSASIGKEY(8) Executable programs IPSEC_RSASIGKEY(8)
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6 ipsec_rsasigkey - generate RSA signature key
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9 ipsec rsasigkey [--verbose] [--seeddev device] [--seed numbits]
10 [--nssdir nssdir] [--password nsspassword] [--hostname hostname]
11 [nbits]
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14 rsasigkey generates an RSA public/private key pair, suitable for
15 digital signatures, of (exactly) nbits bits (that is, two primes each
16 of exactly nbits/2 bits, and related numbers) and emits it on standard
17 output as ASCII (mostly hex) data. nbits must be a multiple of 16.
18 The public exponent is forced to the value 3, which has important speed
20 advantages for signature checking. Beware that the resulting keys have
21 known weaknesses as encryption keys and should not be used for that
22 purpose.
23 The --verbose option makes rsasigkey give a running commentary on
25 standard error. By default, it works in silence until it is ready to
26 generate output.
27 The --seeddev option specifies a source for random bits used to seed
29 the crypto library's RNG. The default is /dev/random (see random(4)).
30 FreeS/WAN and Openswan without NSS support used this option to specify
31 the random source used to directly create keys. Libreswan only uses it
32 to seed the NSS crypto libraries RNG. Under Linux with hardware random
33 support, special devices might show up as /dev/*rng* devices. However,
34 these should never be accessed directly using this option, as hardware
35 failures could lead to extremely non-random values (streams of zeroes
36 have been observed in the wild)
37 The --seedbits option specifies how many seed bits are pulled from the
39 random device to seed the NSS PRNG. The default of 480bit comes from
40 FIPS requirements. Seed bits are rounded up to a multiple of 8.
41 The use of a different random device or a reduction of seedbits from
43 the default value is prevented when the system is running in FIPS mode.
44 The --nssdir option specifies the directory to use for the nss
46 database. This is the directory where the NSS certificate, key and
47 security modules databases reside. The default value is
48 /var/lib/ipsec/nss.
49 The --password option specifies the nss cryptographic module
51 authentication password if the NSS module has been configured to
52 require it. A password is required by hardware tokens and also by the
53 internal software token module when configured to run in FIPS mode. If
54 the argument is /etc/ipsec.d/nsspassword, the password comes from that
55 file; otherwise argument is the password.
56 The US patent on the RSA algorithm expired 20 Sept 2000.
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60 ipsec rsasigkey --verbose 4096
61 generates a 4096-bit signature key and stores this key in the NSS
62 database. The public key can then be extracted and edited into the
63 ipsec.conf (see ipsec_showhostkey(8)).
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66 /dev/random, /dev/urandom
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69 random(4), rngd(8), ipsec_showhostkey(8), Applied Cryptography, 2nd.
70 ed., by Bruce Schneier, Wiley 1996, RFCs 2537, 2313, GNU MP, the GNU
71 multiple precision arithmetic library, edition 2.0.2, by Torbj Granlund
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74 Originally written for the Linux FreeS/WAN project
75 <https://www.freeswan.org> by Henry Spencer. Updated for the Libreswan
76 Project by Paul Wouters.
77 The --round and --noopt options were obsoleted as these were only used
79 with the old non-library crypto code
80 The --random device is only used for seeding the crypto library, not
82 for direct random to generate keys
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85 There is an internal limit on nbits, currently 20000.
86 rsasigkey's run time is difficult to predict, since /dev/random output
88 can be arbitrarily delayed if the system's entropy pool is low on
89 randomness, and the time taken by the search for primes is also
90 somewhat unpredictable. Specifically, embedded systems and most virtual
91 machines are low on entropy. In such a situation, consider generating
92 the RSA key on another machine, and copying ipsec.secrets and the
93 /var/lib/ipsec/nss directory tree to the embedded platform. Note that
94 NSS embeds the full path in the DB files, so the path on proxy machine
95 must be identical to the path on the destination machine.
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98 Paul Wouters
99 placeholder to suppress warning
100libreswan 10/13/2022 IPSEC_RSASIGKEY(8)