Britain and Germany are among the top five countries with the capability to withstand cyberattacks and protect their economies, a study indicates.

The ranking among 19 of the Group of 20 members countries studied is the result of the Cyber Power Index, a study sponsored by Booz Allen Hamilton of the United States and conducted by the Economist Intelligence Unit.

"The Cyber Power Index identifies those countries that understand what it takes to operate in a digital era … and those that don't," said Booz Allen Hamilton Vice Chairman Mike McConnell.

The Cyber Power Index gauges digital adoption, cybersecurity and a country's economic and regulatory environment to cyber-power.

The United States is also on the top five list, as are Australia and Canada. But the report indicated Argentina, Indonesia, Russia and Saudi Arabia are without national cybersecurity plans and don't appear to be making an effort to develop them.

Booze Allen, in announcing the study, said the index produced reflects a weighted mean score by each nation in categories such as legal and regulatory environment, technology infrastructure and industry application of cyber technology and safeguards. Rankings are listed from zero to 100, with 100 being the highest score.

The European Union as a whole was not included in the study.

According to the index, Brazil ranked 10th overall, Russia was 14th, India was 17th and China ranked 13th of the 20 G-20 countries studied. Saudi Arabia came at the bottom of the list.

"Cyber-power relies on a solid foundation that includes technical skills for security and effective use of the cyber environment, high educational attainment levels, open trade policies, and an innovative business environment," the study said.

The analysis concludes the gap in cyber capability between the United States and others is narrowing. South Korea and Japan, for example, are embracing greater levels of bandwidth and communications stability.

Germany scores high in the legal and regulatory category and is only one of five countries with a national cybersecurity plan.

Britain, the United States and Germany are tops in IT access -- the Internet, WiFi, mobile phones. South Africa, Mexico, Indonesia and India afford the least access.