August 30, 1999 Web posted at: 1:41 p.m. EDT (1741 GMT) by Joris Evers, WebWereld Netherlands

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(IDG) -- A team of scientists from six different countries led by Herman te Riele of CWI, the Dutch National research institute for mathematics and computer science, has found the prime factors of a 512-bit number. The size of that number models 95% of the keys used for protection of electronic commerce on the Internet.

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According to the scientists this discovery shows that the popular key size of 512 bits is no longer safe against even a moderately powerful attacker. The amount of money protected by like security keys is immense, as many billions of dollars per day flow through financial institutions such as banks and stock exchanges.

According to CWI's Frans Snijders there are hundreds of thousands 512-bit keys and CWI has cracked only one. "But with the technique we have now we could break every single key," Snijders told Dutch daily NRC Handelsblad. He recommends the standard for encryption to be lifted to 768-bit keys.

The factored key is a model of a so-called 'public key' in the well-known RSA cryptographic system that was designed in the mid-70s by Rivest, Shamir and Adleman at the Massachusetts Institute of Technology in Cambridge, Mass. At present, the 512-bit encryption is used extensively in hardware and software to protect electronic traffic such as in the international version of the Security Sockets Layer handshake protocol.

The factored number, indicated by RSA-155, was taken from the 'RSA Challenge List', which is used as a yardstick for the security of the RSA cryptosystem.

To find the prime factors of RSA-155 about 300 fast SGI and Sun workstations and Pentium PCs were running parallel, continuously - overnight and weekends included - for seven months.