Modern business activities rely on extensive email exchange. Email leakage have become widespread throughout the world, and severe damage has been caused by these leakages it constitutes a problem for organization. The authors study the following problem: a data distributor has given sensitive data to a set of supposedly trusted agents (third parties). If the data distributed to the third parties is found in a public\private domain then finding the guilty party is a nontrivial task to a distributor. Traditionally, this leakage of data has handled by water marking technique which requires modification of data. If the watermarked copy is found at some unauthorized site then distributor claims their ownership.