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Legality and Licencing

Almost all legal issues associated with MacCTC are associated with the CTC library, so for most purposes the licence for MacCTC is identical to the licence for CTC. Except where stated otherwise all of the following applies to both.

This software is the copyright of Ian Miller and Mr. Tines.

This software is free software; you can redistribute it and/or modify it under the terms of the GNU General Public Licence (GPL) as published by the Free Software Foundation (FSF) with one modification. Article 7 of the GPL is waived with respect to the RSA and IDEA patents, for the duration of those patents only. i.e. This software may be distributed in spite of being subject to those patents.

This software is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details .

The following information concerning third party licences has been prepared in good faith and is to the best of the author's knowledge correct. However the authors accept no liability for any errors.

Patents

The document refers to a number of patents. Note that the authors cannot confirm or deny the validity of any of these patents, nor do we challenge them. The courts in the UK have consistently ruled that software algorithms are not patentable, but to date and to the best of the authors' knowledge there has been no challenge to any of these patents. The court's interpretation will vary with jurisdiction.

PGP 2.3

CTC is derived from PGP2.3 (albeit the remaining code is minimal; possibly non-existent), hence the conditions of its licence still apply. The basic licence for PGP2.3 was the same General Public Licence that is used by CTC with the following modifications by Phil Zimmermann:-

"Regardless of and perhaps contrary to some provisions of the FSF General Public License, the following terms apply:
1) Written discussions of PGP in magazines or books may include fragments of PGP source code and documentation, without restrictions.
2) Although the FSF General Public License allows non-proprietary derivative products, it prohibits proprietary derivative products. Despite this, I may grant you a special license if you want to derive a proprietary commercial product from some of PGP's parts. There may or may not be a fee, depending on the circumstances. Retaining my copyright notice and attribution might suffice in some cases. Give me a call and we'll discuss it. I'm real easy to please. Any such license would not free you of any patent licensing requirements. "

To the best of the authors' knowledge these conditions do not modify the GPL at all.

GnuZIP

CTC uses slightly modified versions of GnuZIP for compress/decompress. This is covered by also covered by the GPL.

IDEA

The IDEA (International Data Encryption Algorithm) used by PGP and all PGP compatible programs is patented in most countries by Ascom. They generally allow this to be used without charge for non-commerical use, but commerical users must purchase an end-user licence from Ascom. It is possible to build the CTC library without IDEA to use other ciphers, but then it isn't PGP-compatible. If you distribute CTC derived code including the IDEA algorithm you must include a notice written by Ascom.

MD5

CTC includes message digest code derived from the RSA Data Security, Inc. MD5 Message-Digest Algorithm. The licence requires merely that this is acknowledged. All derived code using this algorithm must also acknowledge this.

RSA

The RSA algorithm is patented in the USA. The patent holders RSADSI Inc. allow the use of the algorithm for non-commerical purposes provided that their library called RSAREF is used to implement it. CTC does not use RSAREF and hence it would be in breach of this patent to use CTC in the USA.

To be legally used in the USA before the patent expires in 2000AD, CTC would have to be modified to have the option of being built with RSAREF. However note that the waiver on article 7 of the GPL expires with the patent. This means that permission to distribute an RSAREF version will expire with the patent, if there are any GPL-incompatible conditions applied to use of the RSAREF library at that time.

Symantec C++ Class Library

This applies only to MacCTC and then only to individuals wishing rebuild their own version from source or inspect the whole source code.

MacCTC is built using the Symantec C++ Class Library version 2.0. This class library is a commerical product of Symantec Corporation. There is no licence required to use an application built using this, but there is a licence required for the Symantec C++ compiler and the Class Library (which is bundled with the compiler). To inspect the library or built your own version of MacCTC you must purchase the compiler from Symantec or one of their distributors. You require version 7.0 or later. (Versions prior to 8.0 were sold as "Think C" rather than "Symantec C".)

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