A way of detecting a watermark present in a structured result, such as a search result or a machine translation. The structured result is received and a hash is computed based upon at least part of the result. The resulting bit sequence is tested against a null hypothesis that the bit sequence was generated by a random variable with a binomial distribution with a parameter p=0.5. The result of this test is compared to a significance level, which indicates whether the structured result is watermarked.