Huang Kexi had an original idea for making money - he bought waste paper from the government of his native Chongqing at almost no cost, scoured it for official documents and sold them for a high price. But the Chongqing branch of the Ministry of State Security revealed on Thursday that it had arrested Huang on June 27 and charged him with illegally obtaining and selling state secrets. Huang started his business in March 1998, going round municipal rubbish dumps and buying waste paper for 2 or 3 yuan (HK$1.88 or HK$2.80) a kg. Then he went through the paper and discovered dozens of official documents. The police accuse Huang of doing this for five years and selling the documents to contacts in Fujian province, who sold them to spies from a 'certain foreign country with outposts in Hong Kong'. The police did not name the country. The ministry said that it seized 172 official documents containing state secrets from Huang. Of these, three were classified as 'top state secrets' and 75 as 'state secrets'. Officials of the ministry were unavailable for comment yesterday and attempts to speak to Huang's family were unsuccessful. The mainland has a sophisticated system of classifying information, with a bureau of the central government in charge of secrets. State security police have broad discretion to interpret the regulations, enabling them to designate a wide range of information as 'secret'.