Security BasicsSymmetric Key | One key is shared by two users both encryption & decryption (substiution cipher, aes, des) | Assymetric | Public and Private Key | Substitution Ciper | Mono-alphabetic cipher 2^n/2 | Diffie-Helman Exchange | Exchanging secret keys over insecure medium. Known large prime and base shared and a secret integer | DES | 56-bit symmetric key, 64bit plain text US standard | AES | Replaces DES 128 bit | Axor0, AxorA | A, 0 | Main Sec. Probs In Mobile? | Config. management, excessive privleges, privacy violations, poor session management | Most problematic part in mobil apps? | Android abstraction layer | Preventing replay attacks? | Use a nonce | Pros of Symmetric Keys | No worry of replay or man in the middle attacks | Agreement on shared key | diffie helman or KDC | Certificate Auth | Binds pub key to part. entity. E registers with CA. When Alice wants bobs pub key, get the certificate, apply CA pub key and get bobs pub key. | Symmetric and Public Key Problems | Sym: establish shared key? (deffie-helman, KDC), Public Key(Man in middle) use CA |
power/energyfactors that affect power | power affects temp, but energy doesn't | equations | power/area proportional to temp | associations | higher current implies high power which increases cpu frequency | thermal runaway | power -> temp -> resistance decrease -> current increase I (cycle) | energy | asffects battery life, power * time = E | energy harvesting | solar, wind -> high capacity, low leakage (low discharge), low capacity, high leakage (quick discharge), appliance |
| | Recent Trends in SecurityID vs Auth | Auth = username + pass, ID = passwd & something like biometric | Data injection | sending false radio signal to pace maker and inducing heart attack | Threat Model/Attack model | What the system thinks about the model. Believes attacker is much more powerful than he actually is. Attack model attacker believes it knows a lot about the system | Key establishment in physi. sec. | Done using human body | Ways to fool machine | brute force feature guess, generate signal (generative), evasion, poison | Evasion attack | create points to gain access without getting caught, alter features | Poison attack | attacker can see the training set, injects their own data at key points, skews the lines | Biometric signals | Signals that don't change like fingerprints | Physiological signals | hard because constantly changing | Hardening Technique | instead of line, have piecewise curves, or instead of line use polygon(polytope) | Internet Control Protocol Messages | agent advertisement, agent solicitation, registration request, registration reply | Foreign Agent | Consumes less ip addresses than mobile host | security performance tradeoff | Increase in security strength -> hardening Hardening implies more difficult classification boundaries May increase False positives or negatives How to find a balance between security strength and performance? Multi-objective optimization problem |
| | Internet of ThingsChallenges of CPS | hard to know how many sensors to use, what data to collect | Cyber Physical Systems | embedding sensors into physical devices | Human to Human interaction | person a thinks about a color red and that dot is displayed to another person in another country | 3 charactertistics of IOT devices | anytime, anything, any place connetion | USN application layer | where apps are built to perform tasks using the sensors through middleware | middleware (Drivers) | allows you to build apps on top of iot sensors | sensor networking layer (bottom) | sensors are launched in environment and report to usn | Difference between gps and tower based location management? | gps needs clear line of sight and is more accurate. Tower based management is bad if you're not near tower, accessibility is less than gps. | what is iot | Network of Physical Objects embedded systems with electronics, software, sensors enable objects to exchange data with manufacturer, operator, other devices through network infrastructure allow remote control direct integration computer + physical world Result: automation in all fields |
Challenges in SecurityChallenges in medical apps | resource constraints in sensors, poor software dev support, real-time requirements for health apps |
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CUDACUDA basics | Terminology Host – The CPU and its memory (host memory) Device – The GPU and its memory (device memory | __global__ | As before, __global__ is a CUDA C keyword meaning — add() will execute on the device — add() will be called from the host | memory management | Host and device memory are distinct entities — Device pointers point to GPU memory May be passed to and from host code May not be dereferenced from host code — Host pointers point to CPU memory May be passed to and from device code May not be dereferenced from device code |
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