O2 (UK) Telefónica O2 had a long-standing relationship with Arsenal F.C., being their shirt sponsor until the end of the 2005/2006 season. In 2005, a three-year deal was signed that saw Telefónica O2 become the team's exclusive mobile communications partner. O2 were the main sponsor of the Channel 4 reality TV show "Big Brother" from its second series (as BT Cellnet) in 2001 until its fourth series in 2003. They also sponsored the spin-off shows "Celebrity Big Brother 2" in 2002 and "" in 2003. In total O2 sponsored five series of the show. O2 sponsored music festivals, the Wireless Festivals, from
Safelayer Secure Communications Safelayer Secure Communications Safelayer Secure Communications S.A. is a Spanish private company founded in May 1999. It develops software products on the Public key infrastructure area (digital security for the identity management, electronic signature and data protection). Safelayer's technology is part of the three major certification and digital identity projects in Spain: Fábrica Nacional de Moneda y Timbre, the Spanish ID card "DNI electrónico" and the Spanish E-passport. Safelayer's technology also secures the NATO X400 messaging system". Safelayer's technology has been and Common Criteria certified. Currently, Safelayer is the only company with a whole family of products CC EAL4+ certified.