path: root/share/man/man8/ssl.8

.Dd March 15, 1999
.Dt SSL 8
.Os
.Sh NAME
.Nm ssl
.Nd details for libssl and libcrypto
.Sh DESCRIPTION
This document describes some of the issues relating to the use of
the OpenSSL libssl and libcrypto libraries. This document
is intended as an overview of what the libraries do, what uses them,
and the slightly unorthodox way of upgrading the library.
.Pp
The SSL libraries (libssl and libcrypto) implement the
.Ar SSL version 2 ,
.Ar SSL version 3 ,
and
.Ar TLS version 1
protocols.
.Ar SSL version 2
and
.Ar 3
are most
commonly used by the
.Ar https
protocol for encrypted web transactions.
Due to patent issues in the United States, there are
problems with shipping a fully functional implementation of these
protocols anywhere in the world, as such shipment would include shipping
.Ar into
the United States, thus causing problems.
.Sh PATENTS AND THE RSA ALGORITHM
.Ar RSA Data Security Inc (RSADSI)
holds a patent on the
.Ar RSA
algorithm in the United States. Because of this, free
implementations of
.Ar RSA
are difficult to distribute and propagate.
(The
.Ar RSA
patent is probably more effective at preventing the widespread
international adoption of integrated crypto than the much maligned
ITAR restrictions are). The versions of libssl and libcrypto
provided in the stock distribution do not contain the
.Ar RSA
algorithm -- all such functions
are stubbed to fail. Since
.Ar RSA
is a key component of
.Ar SSL version 2 ,
this
means that
.Ar SSL version 2
will not work at all.
.Ar SSL version 3
and
.Ar TLS version 1
allow for the exchange of keys via mechanisms that do not
involve
.Ar RSA ,
and will work with the shipped version of the libraries,
assuming both ends can agree to a cipher suite and key exchange that
does not involve RSA.
.Pp
For instance, another typical alternative
is
.Ar DSA
-- which is patent-free.
.Pp
The
.Ar https
protocol used by web browsers (in modern incarnations),
allows for the use of
.Ar SSL version 3
and
.Ar TLS version 1 ,
which in theory allows for encrypted web transactions without using
.Ar RSA .
Unfortunately all the popular web browsers
buy their cryptographic code from
.Ar RSADSI .
Predictably,
.Ar RSADSI
would prefer if web browsers used their patented algorithm, and thus their
libraries do not implement any
.Ar non-RSA
cipher and keying combination.
.Sh HOW TO ADD RSA-CAPABLE LIBRARIES
Fortunately, not all of the world lives in the United
States.
Additionally
.Ar RSADSI
permits non-licensed use of the algorithm by certain parties
(ie. non-commercial use).
If you are permitted to use the
.Ar RSA
algorithm, you can enable the full function of the
.Nm
libraries by updating the shared libraries on your system,
using a command like:
.Bd -literal -offset xxx
# pkg_add ftp://ftp.openbsd.org/pub/OpenBSD/2.6/i386/libssl26.tar.gz
.Ed
.Pp
(Obviously, replace
.Ar 2.6
with the current release, and
.Ar i386
with your architecture name (see
.Xr arch 1 ).
Once your ssl libraries are updated, the ssl libraries will be fully functional.
.Sh SERVER CERTIFICATES
The most common uses of
.Ar SSL/TLS
will require you to generate a server certificate, which is provided by your
host as evidence of its identity when clients make new connections. The
certificates reside in the
.Pa /etc/ssl
directory, with the keys in the
.Pa /etc/ssl/private
directory.
.Pp
Private keys can be encrypted using
.Ar 3DES
and a passphrase to protect their integrity should the encrypted file
be disclosed, However it is
important to note that encrypted server keys mean that the passphrase
needs to be typed in every time the server is started. If a passphrase
is not used, you will need to be absolutely sure your key file
is kept secure.
.Sh GENERATING DSA SERVER CERTIFICATES
Generating a
.Ar DSA
certificate involves several steps. First, you generate
a
.Ar DSA
parameter set with a command like the following:
.Bd -literal -offset indent
# openssl dsaparam 1024 -out dsa1024.pem
.Ed
.Pp
Would generate
.Ar DSA
parameters for 1024 bit
.Ar DSA
keys, and save them to the
file
.Pa dsa1024.pem .
.Pp
Once you have the
.Ar DSA
paramters generated, you can generate a certificate
and unencrypted private key using the command:
.Bd -literal -offset indent
# openssl req -x509 -nodes -newkey dsa:dsa1024.pem \\
  -out /etc/ssl/dsacert.pem -keyout /etc/ssl/private/dsakey.pem
.Ed
.Pp
To generate an encrypted private key, you would use:
.Bd -literal -offset indent
# openssl req -x509 -newkey dsa:dsa1024.pem \\
  -out /etc/ssl/dsacert.pem -keyout /etc/ssl/private/dsakey.pem
.Ed
.Sh GENERATING RSA SERVER CERTIFICATES FOR WEB SERVERS
To generate
.Ar RSA
certificates, you will first need to upgrade your
shared libraries to support
.Ar RSA
as described above. Once that is done,
you can generate
.Ar RSA
certificates that will be usable by
.Xr httpd 8
for
.Ar https
transactions.
.Bd -literal -offset indent
# openssl genrsa -out /etc/ssl/private/server.key 1024
.Ed
.Pp
Or, if you wish the key to be encrypted with a passphrase that you will
have to type in when starting servers
.Bd -literal -offset indent
# openssl genrsa -des3 -out /etc/ssl/private/server.key 1024
.Ed
.Pp
The next step is to generate a
.Ar Certificate Signing Request
which is used
to get a
.Ar Certifying Authority (CA)
to sign your certificate. To do this
use the command:
.Bd -literal -offset indent
# openssl req -new -key /etc/ssl/private/server.key \\
  -out /etc/ssl/private/server.csr
.Ed
.Pp
This
.Pa server.csr
file can then be given to
.Ar Certifying Authority
who will sign the key. One such CA is
.Ar Thawte Certification
which you can reach at
.Ar http://www.thawte.com/.
Thawte can currently sign RSA keys for you. A procedure is being worked out
to allow for DSA keys.
.Pp
You can also sign the key yourself, using the command:
.Bd -literal -offset indent
# openssl x509 -req -days 365 -in /etc/ssl/private/server.csr \\
  -signkey /etc/ssl/private/server.key -out /etc/ssl/server.crt
.Ed
.Pp
With
.Pa /etc/ssl/server.crt
and
.Pa /etc/ssl/private/server.key
in place, you should be able to start
.Xr httpd 8
with the
.Ar -DSSL
flag, enabling
.Ar https
transactions with your machine on port 443.
.Sh BUGS
.Pp
.Nm openssl
and
.Nm libssl
have nearly nonexistent documentation.
Most documentation consists of examples and README files in
the sources.  Mail beck@openbsd.org to assist or
encourage him to finish the job.
.Pp
The world needs more
.Ar DSA
capable
.Ar SSL
and 
.Ar SSH
services, 
.Pp
Patents can be renewed.
.Sh SEE ALSO
.Xr httpd 8 ,
.Xr ssh 1 ,
.Xr sshd 1 ,
.Xr rc 8
.Sh HISTORY
This document first appeared in
.Ox 2.5 .