"If you receive a message from a big sender (like a financial institution, or a major email provider, like Google, Yahoo or Hotmail) that isn't authenticated, this message is most likely forged and you should be careful about replying to it or opening any attachments," Google explained in its Gmail help section.
Authenticate the message.
This example can be extended to illustrate the second basic function of cryptography, providing a means for B to assure himself that an instruction has actually come from A and that it is unaltered i.e., a means of authenticating the message.
The receivers can authenticate the messages by computing only one MAC and hence the figures for -factor 1 is indicative of the energy expense of the receivers.
Sn sends the response message {ID Sn, ID u, ID GW, E X′, T Sn } to U. When U receives Sn's response message {ID Sn, ID u, ID GW, E X′, T Sn } at time T′′′′, U checks this message and authenticates Sn and GW.
Upon verifying this message, the DesDA3C mistakenly authenticates the intruder, acknowledges this to the CA3C and sends the newly derived DesSK as in message 12 and 13a respectively.
For ease of illustration, in the following discussion, we simply use the same key to both encrypt and authenticate a message although two different keys can be used.
Liu et al. in [17] proposed an attribute based multisignature scheme, which allows a number of users to participate to authenticate a message with only one signature.
"This message" in another message.
