Java Cryptography

Cryptography Foundations

Cryptology is the broader field that encompasses both cryptography and cryptanalysis.

Cryptography is the practice of creating secure communication by encoding messages in a way that is difficult to understand by unauthorized parties.

Cryptanalysis is the study of methods for breaking encryption algorithms and protocols without knowing the key.

PlainText-Encryption-CipherText-Decryption-PlainText

The Goals of Cryptography
Confidentiality
Data Integrity
Data Origin Authentication
Entity Authentication
Non-Repudiation

Cryptographic Primitives
Primitives
Encryption
Hash Function
MAC - Message Authentication Code.
Digital Signature



Q. SALT, What Is a Salt?
A salt is:
- A random sequence of bytes
- Combined with the input (e.g., password) before hashing
- Used to prevent attacks like rainbow table lookups or precomputed hash collisions
Without a salt:
- Two users with the same password will have the same hash. With a salt:
- Even identical passwords produce different hashes, making brute-force and lookup attacks far harder.


Q. What Is a Private Key?
A private key is:
- A secret cryptographic key known only to the owner
- Paired with a public key in asymmetric algorithms like RSA or EC
- Used to decrypt data encrypted with the public key
- Used to sign data so others can verify it with the public key


Comments

Post a Comment

Popular posts from this blog

Java 25 Features

Java 25 Features Major Features in Java SE 25 1. Scoped Values (Finalized) Scoped values provide a safer alternative to thread-local variables, allowing values to be shared across threads in a controlled way. ```java import java.util.concurrent.Executors; import jdk.incubator.concurrent.ScopedValue; public class ScopedValueDemo {     static final ScopedValue<String> USER = ScopedValue.newInstance();     public static void main(String[] args) {         ScopedValue.where(USER, "Alice").run(() -> {             System.out.println("Running as user: " + USER.get());             Executors.newSingleThreadExecutor().submit(() ->                 System.out.println("Child thread user: " + USER.get())             );         });     } } ``` 2. Flexible Constructor Bodies Constructors now all...
Read more

Java Version Features

Java has evolved significantly from JDK 1.0 to Java 22, introducing powerful features like lambdas, modules, records, virtual threads, and structured concurrency. Java Version Highlights Version | Key Features Java 8 (2014) | Lambda expressions, Streams API, Optional, Default methods, Nashorn JS engine Java 9 (2017) | Module system (Project Jigsaw), JShell, Stream improvements Java 10 (2018) | Local variable type inference (`var`) Java 11 (2018) | New HTTP Client API, String methods, Flight Recorder, Removed deprecated APIs Java 12 (2019) | Switch expressions (preview), Shenandoah GC Java 13 (2019) | Text blocks (preview) Java 14 (2020) | Records (preview), Pattern matching for instanceof (preview) Java 15 (2020) | Sealed classes (preview), Hidden classes Java 16 (2021) | Records, Pattern matching, JEP 376: ZGC improvements Java 17 (2021) | Sealed classes, Pattern matching, Foreign function & memory API (preview) Java 18 (2022) | Simple web server, UTF-8 by default, Code snip...
Read more

Java 8 Programs

Java 8 Programs Program to ADD PREFIX and SUFFIX to the STRING? - StringJoiner class, used to add prefix and suffix in a given String      StringJoiner stringJoiner = new StringJoiner(",", "#", "#");      stringJoiner.add("Interview");      stringJoiner.add("Questions");      stringJoiner.add("Answers");      System.out.println(stringJoiner); Program to PRINT 10 RANDOM NUMBERs using forEach? - Use Random class to generate Random number      Random random = new Random();      random.ints().limit(10).forEach(System.out::println); Program to iterate a Stream using the forEach method?      List<String> str = Arrays.asList("Hello","Hola","Namaste","Hi");      str.stream().forEach(System.out::println); Program to find the Minimum and Maximum number of a Stream? To find minimum or maximum number in stream, use comparator.comparing() method which will take...
Read more