VeriSign's  chief executive Stratton Sclavos has mysteriously resigned.

Analysts were shocked by the abrupt departure and VeriSign refused to give many details.Sclavos has been at the helm for 12 years. William Roper, the former chief financial officer of government technology contractor Science Applications International, was appointed to succeed Sclavos.

Sclavos has also stepped down as chairman. The board elected Edward Mueller, former chief executive of home furnishings retailer Williams-Sonoma to take over.Analysts do not know what to make of the announcement as Sclavos was fairly popular.

However they believe there might have been intractable disagreements with the board, and the desire by directors to install fresh.