Skip to main content

Cryptography

Crypto - Secret
Graphy - To Write

CryptoLogy - The science of secrets

Symmetric Cryptography: Both the parties have the same keys.
Asymmetric Cryptography: Both the parties do not have the same keys. They work on the concept of Public and Private Keys. Its also called as Public Key Cryptography.

Its very expensive to encrypt and decrypt using Asymmetric Cryptography. Hence there are systems which use both Symmetric and Asymmetric Cryptography together like ECC.

Don't implement your own Crypto. Its very easy to do it incorrectly.

Side Channel: When you can observer properties of a function other than their functional behaviour it is called as Side Channel. E.g. Knowing how long it takes to encrypt a text, knowing the length of a particular encrypted text.

In cryptography, Kerckhoffs's principle (also called Kerckhoffs's desideratum, assumption, axiom, doctrine or law) was stated by Netherlands born cryptographer Auguste Kerckhoffs in the 19th century: A cryptosystem should be secure even if everything about the system, except the key, is public knowledge.


Comments

Popular posts from this blog

Some good links

https://www.html5rocks.com/en/tutorials/internals/howbrowserswork/ http://taligarsiel.com/ClientSidePerformance.html -- Client side performance tips https://ariya.io/ https://vertx.io/docs/ -- New exciting Framework, Must read. https://javaee.github.io/ -- Very good resource to see various javaee projects and explore enterprise architecture and design concepts. https://projects.eclipse.org/projects/ee4j -- Lots of interesting open source projects by eclipse http://openjdk.java.net/projects/mlvm/ -- the main project for supporting more dynamic languages to jvm. http://esprima.org/ -- EcmaScript parser http://c2.com/ppr/ and http://hillside.net/ -- Good place to learn patterns http://cr.openjdk.java.net/~briangoetz/lambda/Defender%20Methods%20v4.pdf https://validator.w3.org/nu/ -- This will validate your website css and js https://www.cellstream.com/intranet/reference-reading/faq/216-what-is-2-128.html http://shattered.io/ -- An example of SHA1 collision attack.

@MappedSuperclass vs. @Inheritance

MappedSuperClass must be used to inherit properties, associations, and methods. Entity inheritance must be used when you have an entity, and several sub-entities. You can tell if you need one or the other by answering this questions: is there some other entity in the model which could have an association with the base class? If yes, then the base class is in fact an entity, and you should use entity inheritance. If no, then the base class is in fact a class that contains attributes and methods that are common to several unrelated entities, and you should use a mapped superclass. For example: You can have several kinds of messages: SMS messages, email messages, or phone messages. And a person has a list of messages. You can also have a reminder linked to a message, regardless of the kind of message. In this case, Message is clearly an entity, and entity inheritance must be used. All your domain objects could have a creation date, modification date and ID, and you could thus

Hashmap Keyset and EntrySet difference.

If you're concerned about performance when iterating through your hash map, I suggest you have a look at  LinkedHashMap . From the docs: Iteration over the collection-views of a LinkedHashMap requires time proportional to the size of the map, regardless of its capacity. Iteration over a HashMap is likely to be more expensive, requiring time proportional to its capacity. HashMap.entrySet() The source-code for this implementation is available. The implementation basically just returns a new  HashMap.EntrySet . A class which looks like this: private final class EntrySet extends AbstractSet < Map . Entry < K , V >> { public Iterator < Map . Entry < K , V >> iterator () { return newEntryIterator (); // returns a HashIterator... } // ... } and a  HashIterator  looks like private abstract class HashIterator < E > implements Iterator < E > { Entry < K , V > next ; // next entry to ret