Digital signatures having an embedded view of signed data that lock the signed data but permit it to be repurposed are described. One of these digital signatures can be repurposed for signature by others, such as co-signers or counter-signers. Another of these digital signatures includes embedded information...http://www.google.de/patents/US7568101?utm_source=gb-gplus-sharePatent US7568101 - Digital signatures with an embedded view
