Types of Signatures Direct digital signature involves only the communicating parties v Assumed that receiver knows public key of sender Signature may be formed by(1)encrypting entire message with sender's private key or(2 encrypting hash code of message with senders private key. Y Further encryption of entire message signature with receiver's public key or shared private key ensures confidentiality6 Types of Signatures • Direct digital signature – involves only the communicating parties ✓Assumed that receiver knows public key of sender. ✓Signature may be formed by (1) encrypting entire message with sender’s private key or (2) encrypting hash code of message with sender’ s private key. ✓Further encryption of entire message + signature with receiver’s public key or shared private key ensures confidentiality