Block Size 64 Bits 128 Bits Security Level Considered weak Strong and Secure Speed Faster on Older Hardware Efficient on Modern Hardware Use Cases Legacy Systems, Encryption of small data sizes Modern Applications, Secure Communications and File Encryption

Asymmetric Encryption

Asymmetric encryption, unlike its symmetric counterpart, employs a pair of keys: a public key for encryption and a private key for decryption. This method enhances security by allowing users to share their public keys openly while keeping their private keys confidential. Two widely recognized asymmetric encryption methods are RSA (Rivest–Shamir–Adleman) and Diffie-Hellman.

RSA (Rivest–Shamir–Adleman)

RSA, one of the first public-key cryptosystems, is based on the mathematical difficulty of factoring large prime numbers. It allows secure data transmission and digital signatures, making it foundational in modern cryptographic practices.

Key Features of RSA

RSA's strength lies in its robust key generation and security features. The key pair generation process involves selecting two large prime numbers, p and q, which are multiplied to produce n. The public key consists of n and an exponent e, while the private key comprises n and another exponent d, calculated to ensure e⋅d ≡ 1 mod ϕ(n), where ϕ is Euler's totient function.

Diffie-Hellman Key Exchange Process

Diffie-Hellman, on the other hand, is not an encryption method but a key exchange algorithm. It enables two parties to securely generate and share a common secret key over an insecure channel. This shared key can then be used for symmetric encryption, combining the strengths of both encryption types for secure communications.

The Diffie-Hellman key exchange process enables two parties to establish a shared secret key over an unsecured channel. The algorithm operates as follows:

Public Parameters: Both parties agree on a large prime number p and a base g (generator).
Private Keys: Each party selects a private key (e.g., Alice chooses a and Bob chooses b), keeping them secret.
Compute Public Keys: Alice computes her public key A = g^a mod p and sends it to Bob. Bob computes his public key B = g^b mod p and sends it to Alice.
Compute Shared Secret: Both parties can now compute the shared secret using the received public key and their private key. Alice computes S = B^a mod p, while Bob computes S = A^b mod p. The shared secret S will be the same for both parties.

Real-World Applications of Each Encryption Method

Symmetric Encryption Applications

File Encryption: Organizations often encrypt sensitive files using AES to protect data at rest, ensuring unauthorized access is prevented.
VPNs: Symmetric encryption is used to encrypt data traffic in Virtual Private Networks, providing secure remote access to private networks.
Disk Encryption: Tools like BitLocker and VeraCrypt utilize symmetric encryption to secure entire disk volumes.

Asymmetric Encryption Applications

Secure Web Browsing (HTTPS): RSA is commonly