Unauthorised duplication and/or use of computer software. This usually means unauthorised copying, either by individuals for use by themselves or their friends or by companies who then sell the illegal copies to users. Many kinds of software protection have been invented to try to reduce software theft but, with sufficient effort, it is always possible to bypass or "crack" the protection, and software protection is often annoying for legitimate users.
Software theft in 1994 was estimated to have cost $15 billion in worldwide lost revenues to software publishers. It is an offence in the UK under the Copyright, Designs and Patents Act 1988, which states that "The owner of the copyright has the exclusive right to copy the work."
It is estimated that European software houses alone lose $6 billion per year through the unlawful copying and distribution of software, with much of this loss being through business users rather than "basement hackers". One Italian pirating operation employed over 100 staff and had a turnover of $10M.
It is illegal to: 1. Copy or distribute software or its documentation without the permission or licence of the copyright owner. 2. Run purchased software on two or more computers simultaneously unless the licence specifically allows it. 3. Knowingly or unknowingly allow, encourage or pressure employees to make or use illegal copies sources within the organisation. 4. Infringe laws against unauthorised software copying because someone compels or requests it. 5. Loan software in order that a copy be made of it.
When software is upgraded it is generally the case that the licence accompanying the new version revokes the old version. This means that it is illegal to run both the old and new versions as only the new version is licensed.
Both individuals and companies may be convicted of piracy offences. Officers of a company are also liable to conviction if the offences were carried out by the company with their consent. On conviction, the guilty party can face imprisonment for up to two years (five in USA), an unlimited fine or both as well as being sued for copyright infringement (with no limit) by the copyright owner.