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Copyright (c) 1995-1998 Eric A. Young, Tim J. Hudson
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All rights reserved.
DESCRIPTION
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The OpenSSL Project is a collaborative effort to develop a robust,
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commercial-grade, fully featured, and Open Source toolkit implementing the
Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1)
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protocols with full-strength cryptography world-wide. The project is managed
by a worldwide community of volunteers that use the Internet to communicate,
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OpenSSL is based on the excellent SSLeay library developed from Eric A. Young
and Tim J. Hudson. The OpenSSL toolkit is licensed under a dual-license (the
OpenSSL license plus the SSLeay license) situation, which basically means
that you are free to get and use it for commercial and non-commercial
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OVERVIEW
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The OpenSSL toolkit includes:
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libssl.a:
Implementation of SSLv2, SSLv3, TLSv1 and the required code to support
both SSLv2, SSLv3 and TLSv1 in the one server and client.
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libcrypto.a:
General encryption and X.509 v1/v3 stuff needed by SSL/TLS but not
actually logically part of it. It includes routines for the following:
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Ciphers
libdes - EAY's libdes DES encryption package which has been floating
around the net for a few years. It includes 15
'modes/variations' of DES (1, 2 and 3 key versions of ecb,
cbc, cfb and ofb; pcbc and a more general form of cfb and
ofb) including desx in cbc mode, a fast crypt(3), and
routines to read passwords from the keyboard.
RC4 encryption,
RC2 encryption - 4 different modes, ecb, cbc, cfb and ofb.
Blowfish encryption - 4 different modes, ecb, cbc, cfb and ofb.
IDEA encryption - 4 different modes, ecb, cbc, cfb and ofb.
Digests
MD5 and MD2 message digest algorithms, fast implementations,
SHA (SHA-0) and SHA-1 message digest algorithms,
MDC2 message digest. A DES based hash that is popular on smart cards.
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Public Key
RSA encryption/decryption/generation.
There is no limit on the number of bits.
DSA encryption/decryption/generation.
There is no limit on the number of bits.
Diffie-Hellman key-exchange/key generation.
There is no limit on the number of bits.
X.509v3 certificates
X509 encoding/decoding into/from binary ASN1 and a PEM
based ascii-binary encoding which supports encryption with a
private key. Program to generate RSA and DSA certificate
requests and to generate RSA and DSA certificates.
Systems
The normal digital envelope routines and base64 encoding. Higher
level access to ciphers and digests by name. New ciphers can be
loaded at run time. The BIO io system which is a simple non-blocking
IO abstraction. Current methods supported are file descriptors,
sockets, socket accept, socket connect, memory buffer, buffering, SSL
client/server, file pointer, encryption, digest, non-blocking testing
and null.
Data structures
A dynamically growing hashing system
A simple stack.
A Configuration loader that uses a format similar to MS .ini files.
openssl:
A command line tool that can be used for:
Creation of RSA, DH and DSA key parameters
Creation of X.509 certificates, CSRs and CRLs
Calculation of Message Digests
Encryption and Decryption with Ciphers
SSL/TLS Client and Server Tests
Handling of S/MIME signed or encrypted mail
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PATENTS
-------
Various companies hold various patents for various algorithms in various
locations around the world. _YOU_ are responsible for ensuring that your use
of any algorithms is legal by checking if there are any patents in your
country. The file contains some of the patents that we know about or are
rumoured to exist. This is not a definitive list.
RSA Data Security holds software patents on the RSA and RC5 algorithms. If
their ciphers are used used inside the USA (and Japan?), you must contact RSA
http://www.rsa.com/.
RC4 is a trademark of RSA Data Security, so use of this label should perhaps
only be used with RSA Data Security's permission.
The IDEA algorithm is patented by Ascom in Austria, France, Germany, Italy,
Japan, Netherlands, Spain, Sweden, Switzerland, UK and the USA. They should
be contacted if that algorithm is to be used, their web page is
http://www.ascom.ch/.
INSTALLATION
------------
To install this package under a Unix derivative, read the INSTALL file. For
a Win32 platform, read the INSTALL.W32 file. For OpenVMS systems, read
INSTALL.VMS.
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For people in the USA, it is possible to compile OpenSSL to use RSA Inc.'s
public key library, RSAREF, by configuring OpenSSL with the option "rsaref".
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Read the documentation in the doc/ directory. It is quite rough, but it
lists the functions, you will probably have to look at the code to work out
how to used them. Look at the example programs.
SUPPORT
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If you have any problems with OpenSSL then please take the following steps
first:
- Download the current snapshot from ftp://ftp.openssl.org/snapshot/
to see if the problem has already been addressed
- Remove ASM versions of libraries
- Remove compiler optimisation flags
If you wish to report a bug then please include the following information in
any bug report:
- On Unix systems:
Self-test report generated by 'make report'
- On other systems:
OpenSSL version: output of 'openssl version -a'
OS Name, Version, Hardware platform
Compiler Details (name, version)
- Application Details (name, version)
- Problem Description (steps that will reproduce the problem, if known)
- Stack Traceback (if the application dumps core)
Report the bug to the OpenSSL project at:
Note that mail to openssl-bugs@openssl.org is forwarded to a public
mailing list. Confidential mail may be sent to openssl-security@openssl.org
(PGP key available from the key servers).
HOW TO CONTRIBUTE TO OpenSSL
----------------------------
Development is coordinated on the openssl-dev mailing list (see
http://www.openssl.org for information on subscribing). If you
would like to submit a patch, send it to openssl-dev@openssl.org with
the string "[PATCH]" in the subject. Please be sure to include a
textual explanation of what your patch does.
The preferred format for changes is "diff -u" output. You might
generate it like this:
# cd openssl-work
# [your changes]
# ./Configure dist; make clean
# cd ..
# diff -urN openssl-orig openssl-work > mydiffs.patch