More Definitions unconditional security computational security
{"Image DocumentName": "More Definitions unconditional security computational security", "Image ImageDescription": "no matter how much computer power or time is available, the cipher cannot be broken since the ciphertext provides insufficient information to uniquely determine the corresponding plaintext. computational security. given limited computing resources (e.g., time needed for calculations is greater than age of universe), the cipher cannot be broken. Two more definitions are worthy of note. An encryption scheme is unconditionally secure if the ciphertext generated by the scheme does not contain enough information to determine uniquely the corresponding plaintext, no matter how much ciphertext is available. An encryption scheme is said to be computationally secure if either the cost of breaking the cipher exceeds the value of the encrypted information, or the time required to break the cipher exceeds the useful lifetime of the information. Unconditional security would be nice, but the only known such cipher is the one-time pad (later). For all reasonable encryption algorithms, we have to assume computational security where it either takes too long, or is too expensive, to bother breaking the cipher.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}