Unconditional vs. Conditional Security
The cryptographic constructions (also referred to later on as cryptographic schemes) are built to stand against adversaries that mount intentional attacks (see Crypt(?) ). In general, we aim for powerful adversaries: a cryptographic construction that stands against one adversary also stands against weaker adversaries (i.e., adversaries with less capabilities). So, the stronger the adversary is, the better (i.e., more secure) the scheme is. The most powerful adversary we can think of is unbounded in the sense that he/she can use infinite resources (e.g., unlimited computational power and time). A cryptographic construction that fully stands against an unbounded adversary is called unconditionally secure or information-theoretically secure. Examples of information-theoretically secure schemes include One Time Pad (OTP) [1] and Shamir's secret sharing scheme [2 ] . ...