5. The method as claimed in claim 2 , wherein the transformation of the decrypted document fragment of the source document is a changing a visual characteristic of the decrypted document fragment of the source document.
5. The method as claimed in claim 2 , wherein the transformation of the decrypted document fragment of the source document is a changing a visual characteristic of the decrypted document fragment of the source document. 8. The method as claimed in claim 5 , wherein the changed visual characteristic of the decrypted document fragment is color.