Symmetric/Asymmetric Encryption and Digital Signatures
Learn about the fundamentals of symmetric and asymmetric encryption in distributed systems. Understand how intractable problems underpin public-key cryptography, key exchange methods like Diffie-Hellman, and the use of digital signatures for data integrity. This lesson equips you to grasp essential security mechanisms important for protecting distributed applications.
As we have already explained, symmetric cryptography is mainly based on randomization. On the other hand, asymmetric cryptography does not rely only on randomization because it allows an easy computation in the forward direction (e.g., generating the key pair), but makes the inverse computation extremely hard (e.g. discovering the private key from the public key). The main building block for asymmetric cryptography is so-called intractable problems.
Intractable problems
Intractable problems are problems for which there is no known efficient algorithm to solve.
Types
There are two main types of intractable problems: