Abstract: Cryptographic Key Management System facilitating secure access of data portions to corresponding groups of users. In an embodiment, corresponding group key (asymmetric key pair) is provided for each group, with the private key being stored in a secure format requiring the user credentials for decryption. In addition, a data key required to decrypt a data portion of interest is encrypted using the group public key. Thus, when a user attempts to access a data portion, the user credentials are used to decrypt the group private key, which is then used to decrypt the data key. The data key is then used to decrypt the data portion of interest.

Abstract: Two digital signatures are generated associated with an electronic document. One digital signature (“content signature”) maybe based on a user input contained in the document and another digital signature (“document signature”) may be based on a stream of data representing the document. The document is sent along with the two signatures to a receiver system. The receiver system can verify the integrity of the document (and thus the user input) based on one or both of the signatures. Optionally, multiple content signatures may be used with each content signature being generated based on a portion of a document. In addition, each document may contain a control section which includes rules specifying permitted/prohibited actions against each portion.