.IR group ]
.RB [ \-a
.IR socket ]
+.RB [ \-m
+.IR mode ]
.RB [ \-T
.IR trace-opts ]
.br
.BR tripe\-admin (5)).
.hP 3.
It loads the private key with the tag or type name
+.B tripe
+(or, failing that,
.B tripe\-dh
-from the Catacomb-format file
+for backwards compatibility reasons) from the Catacomb-format file
.BR keyring ,
and loads the file
.B keyring.pub
administration socket.
.TP
.BI "\-G, \-\-setgid=" group
-Set gid to that of
+If the current effective uid is zero (i.e., the daemon was invoked as
+.BR root )
+then set gid to that of
.I group
-(either a group name or integer gid) after initialization.
+(either a group name or integer gid) after initialization. In any
+event, arrange hat the administration socket be owned by the given
+.IR group .
.TP
.BI "\-k, \-\-priv\-keyring=" file
Reads the private key from
Uses the private key whose tag or type is
.I tag
rather than the default
+.B tripe
+or
.BR tripe\-dh .
.TP
.BI "\-a, \-\-admin\-socket=" socket
.B "\*(/s/tripesock"
is used instead.
.TP
+.BI "\-m, \-\-admin\-perms=" mode
+Permissions (as an octal number) to set on the administration socket. The
+default is 600, which allows only the socket owner. Setting 660 allows
+members of the
+.I group
+configured through the
+.B \-G
+option to connect to the socket, which may be useful. Allowing world access
+is a terrible idea.
+.TP
.BI "\-T, \-\-trace=" trace-opts
Allows the enabling or disabling of various internal diagnostics. See
below for the list of options.
-.SS "Setting up a VPN with tripe"
+.SS "Key exchange group types"
The
.B tripe
-server identifies peers by name. While it's
-.I possible
-for each host to maintain its own naming system for its peers, this is
-likely to lead to confusion, and it's more sensible to organize a naming
-system that works everywhere. How you manage this naming is up to you.
-The only restriction on the format of names is that they must be valid
-Catacomb key tags, since this is how
+server uses Diffie\(en\&Hellman key exchange to agree the symmetric keys
+used for bulk data transfer. Currently
.B tripe
-identifies which public key to use for a particular peer: they may not
-contain whitespace characters, or a colon
-.RB ` : '
-or dot
-.RB ` . ',
+can do Diffie\(en\&Hellman in two different kinds of cyclic groups:
+.I "Schnorr groups"
+(denoted
+.BR dh )
+and
+.I "elliptic curve groups"
+(denoted
+.BR ec ).
.PP
-Allocating IP addresses for VPNs can get quite complicated. I'll
-attempt to illustrate with a relatively simple example. Our objective
-will be to set up a virtual private network between two sites of
-.BR example.com .
-The two sites are using distinct IP address ranges from the private
-address space described in RFC1918: site A is using addresses from
-10.0.1.0/24 and site B is using 10.0.2.0/24. Each site has a gateway
-host set up with both an address on the site's private network, and an
-externally-routable address from the public IP address space. Site A's
-gateway machine,
-.BR alice ,
-has the addresses 10.0.1.1 and 200.0.1.1; site B's gateway is
-.B bob
-and has addresses 10.0.2.1 and 200.0.2.1.
-.hP 1.
-Install
-.B tripe
-on both of the gateway hosts. Create the directory
-.BR /var/lib/tripe .
-.hP 2.
-On
-.BR alice ,
-make
-.B /var/lib/tripe
-the current directory and generate a Diffie-Hellman group:
-.RS
+A Schnorr group is a prime-order subgroup of the multiplicative group of
+a finite field; this is the usual
+.I g\*(ssx\*(se
+mod
+.I p
+kind of Diffie\(en\&Hellman. An elliptic curve group is a prime-order
+subgroup of the abelian group of
+.BR K -rational
+points on an elliptic curve defined over a finite field
+.BR K .
+.PP
+Given current public knowledge, elliptic curves can provide similar or
+better security to systems based on integer discrete log problems,
+faster, and with less transmitted data. It's a matter of controversy
+whether this will continue to be the case. The author uses elliptic
+curves.
+.PP
+The server works out which it should be doing based on the key's
+.B kx-group
+attribute, which should be either
+.B dh
+or
+.BR ec .
+If this attribute isn't present, then the key's type is examined: if
+it's of the form
+.BR tripe\- group
+then the
+.I group
+is used. If no group is specified,
+.B dh
+is used as a fallback.
+.PP
+To create usual Schnorr-group keys, say something like
.VS
-key add \-adh\-param \-LS \-b2048 \-B256 \e
- \-eforever \-tparam tripe\-dh\-param
+key add \-adh-param \-LS \-b3072 \-B256 \e
+ \-eforever \-tparam tripe\-param kx-group=dh
.VE
-(See
-.BR key (1)
-from the Catacomb distribution for details about the
-.B key
-command.) Also generate a private key for
-.BR alice :
+to construct a parameters key; and create the private keys by
.VS
key add \-adh \-pparam \-talice \e
- \-e"now + 1 year" tripe\-dh
+ \-e"now + 1 year" tripe
.VE
-Extract the group parameters and
-.BR alice 's
-public key to
-.I separate
-files, and put the public key in
-.BR keyring.pub :
-.VS
-key extract param param
-key extract \-f\-secret alice.pub alice
-key \-kkeyring.pub merge alice.pub
-.VE
-Send the files
-.B param
-and
-.B alice.pub
-to
-.B bob
-in some secure way (e.g., in PGP-signed email, or by using SSH), so that
-you can be sure they've not been altered in transit.
-.RE
-.hP 3.
-On
-.B bob
-now, make
-.B /var/lib/tripe
-the current directory, and import the key material from
-.BR alice :
-.RS
+To create elliptic curve keys, say something like
.VS
-key merge param
-key \-kkeyring.pub merge alice.pub
-.VE
-Generate a private key for
-.B bob
-and extract the public half, as before:
-.VS
-key add \-adh \-pparam \-tbob \e
- \-e"now + 1 year" tripe\-dh
-key extract \-f\-secret bob.pub bob
-key \-kkeyring.pub merge bob.pub
-.VE
-and send
-.B bob.pub
-back to
-.B alice
-using some secure method.
-.RE
-.hP 4
-On
-.BR alice ,
-merge
-.B bob 's
-key into the public keyring. Now, on each host, run
-.RS
-.VS
-key \-kkeyring.pub fingerprint
-.VE
-and check that the hashes match. If the two sites have separate
-administrators, they should read the hashes to each other over the
-telephone (assuming that they can recognize each other's voices).
-.RE
-.hP 5.
-Start the
-.B tripe
-servers up. Run
-.RS
-.VS
-tripectl \-slD
-.VE
-on each of
-.B alice
-and
-.BR bob .
-.RE
-.hP 6.
-To get
-.B alice
-talking to
-.BR bob ,
-run this shell script (or one like it):
-.RS
-.VS
-#! /bin/sh
-
-tripectl add bob 200.0.2.1 4070
-ifname=`tripectl ifname bob`
-ifconfig $ifname 10.0.1.1 pointopoint 10.0.2.1
-route add -net \e
- 10.0.2.0 netmask 255.255.255.0 \e
- gw 10.0.2.1
-.VE
-Read
-.BR ifconfig (8)
-and
-.BR route (8)
-to find out about your system's variants of these commands. The
-versions shown above assume a Linux system.
-Run a similar script on
-.BR bob ,
-to tell its
-.B tripe
-server to talk to
-.BR alice .
-.RE
-.hP 7.
-Congratulations. The two servers will exchange keys and begin sending
-packets almost immediately. You've set up a virtual private network.
-.SS "Using elliptic curve keys"
-The
-.B tripe
-server can use elliptic curve Diffie-Hellman for key exchange, rather
-than traditional integer Diffie-Hellman. Given current public
-knowledge, elliptic curves can provide similar or better security to
-systems based on integer discrete log problems, faster, and with less
-transmitted data. It's a matter of controversy whether this will
-continue to be the case. The author uses elliptic curves.
-.PP
-The server works out which it
-should be doing based on the key type, which is either
-.B tripe\-dh
-for standard Diffie-Hellman, or
-.B tripe\-ec
-for elliptic curves. To create elliptic curve keys, say something like
-.VS
-key add \-aec\-param \-Cnist-p192 \-eforever \e
- \-tparam tripe\-ec\-param
+key add \-aec\-param \-Cnist-p256 \-eforever \e
+ \-tparam tripe\-param kx-group=ec
.VE
to construct a parameters key, using your preferred elliptic curve in
the
for details); and create the private keys by
.VS
key add \-aec \-pparam \-talice \e
- \-e"now + 1 year" tripe\-ec
+ \-e"now + 1 year" tripe
.VE
-Now start
-.B tripe
-with the
-.B \-ttripe\-ec
-option, and all should be well.
+Note that the
+.BR tripe-keys (8)
+program provides a rather more convenient means for generating and
+managing keys for
+.BR tripe .
.SS "Using other symmetric algorithms"
The default symmetric algorithms
.B tripe
.
.BR key (1),
.BR tripectl (1),
-.BR tripe\-admin (5).
+.BR tripe\-admin (5),
+.BR tripe\-keys (8).
.PP
.IR "The Trivial IP Encryption Protocol" ,
.IR "The Wrestlers Protocol" .
~mdw / tripe / blobdiff