Tzachi Wiesenfeld probably has access to most of the world's buildings. If not, he could no doubt find a way of getting in.

The Israeli engineer is the vice president of Assa Abloy, the world's leading door solutions and lock company. He heads the Europe, Middle East and Africa multi-billion dollar arm - the group's largest division.

Formed in 1994, Assa Abloy owns 100 brands and employs 40,000 people. It expects to generate more than €4 billion (£3.4 billion) worth of sales this year.

The group provides traditional mechanical locks - such as door locks and cylinders - to more high-tech offerings: smart cards, access control systems and keyless entries. It is the latter that the group is really focusing on.

Mr Wiesenfeld, 56, says: "We are not phasing out our mechanical part but there is a big focus today on digital solutions. That's where the industry is going. That's where the trend is and where we are putting a lot of our money."

The company employs around 1,000 development engineers and 20 per cent of sales are products introduced over the past three years. Among them, and making the headlines: mobile phone keys.

Assa Abloy has created a technology that enables people to open doors using their mobile. The infrastructure is already available in hotels as a world-first.

Authorised guests receive a text message prior to check-in with their room number. They hold the phone up to the door and swipe it against the card reader, bypassing reception. The firm is collaborating with BlackBerry's maker Research In Motion, which is to include the technology in its upcoming models.

What's more, Mr Wiesenfeld says the service will be available for residential homes next year. In fact he says it is only a matter of time before mobile keys replace the need for mechanical ones.

"We are moving towards convenience security. Take automatic doors for instance, it's high security combined with convenience.

"When it comes to opening our homes we have been using the same method for years. But people will realise the benefit of not carrying a bunch of keys around and just using their mobile phone, which they take everywhere with them anyway. This will be the trigger to the change."

What happens if you lose your phone? "Tell the company and the authorisation is cancelled. You will be given a bypass key to access your home or you can use a different authorised phone."

He values the potential market at "hundreds of millions of euros, even more - but it will take a few years to get there."

Another huge growth area is the firm's CLIQ technology. This enables remote access to sites to be authorised via the internet. It is aimed at firms with doors that demand registered and controlled security, such as utility companies where a technician might need to get on site.

"If one person loses the key you need to replace the entire system. This could be 500 locks, which is time consuming and could jeopardise security."

Launched in May, sales of CLIQ Remote are growing exponentially and are expected to be worth around €50 million next year (around £43 million). It recently picked up the best innovation award at IFSEC global security exhibition in Birmingham.

Mr Wiesenfeld, who studied at the Technion, Bar-Ilan University and London Business School, joined Assa Abloy in 2000 when the company bought Israel's Mul-T-Lock. He was chief executive of Mul-T-Lock at the time. Mr Wiesenfeld took over as Assa Abloy UK's managing director before being promoted to vice president of the entire group.

Now based in Surrey, he remains chair of Mul-T-Lock, one of Assa Abloy's 300 purchases over the past 17 years. It also owns Yales, Chubb and Sargent.

Traded on the Stockholm Stock Exchange, Assa Abloy has a market capital of around €6.5 billion (£5.6 billion). Its share price has grown from around six Swedish Kronos (around 56 pence today) in 1994 to around 160 Swedish Kronas (£15).

"Things are moving very fast for us. They are very exciting times and also frightening. The digital world can be daunting. You think: 'Oh gosh, what have I missed today?' You have to keep coming up with smarter things." No doubt Assa Abloy will.