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Cryptography

Topic 3: Asymmetric Encryption and Algorithms

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Understanding Asymmetric Encryption:

Asymmetric encryption, also known as public-key cryptography, harnesses a pair of keys – a public key and a private key.

  • The public key is openly shared for sending encrypted messages to the holder of the corresponding private key. When a sender encrypts a message using the recipient's public key, only the recipient's private key can decrypt it. This distinctive approach ensures secure communication, as the private key remains secluded and is never transmitted.

  • It is pivotal in upholding data confidentiality, integrity, and authenticity in the digital landscape.

  • Despite its robust security advantages, asymmetric encryption can be computationally intensive compared to symmetric encryption. It is not well suited for encrypting large volumes of data.

  • Asymmetric Encryption Algorithms:

    • RSA (Rivest–Shamir–Adleman)

    • ECC (Elliptic Curve Cryptography)

    • DSA (Digital Signature Algorithm)

    • Diffie-Hellman (used for key exchange)

Strong Asymmetric Encryption Algorithms

RSA (Rivest–Shamir–Adleman)

  • RSA supports various key lengths, with 2048 and 3072 bits commonly used. Higher key lengths, such as 4096 bits, offer increased security.

  • RSA's security relies on the difficulty of factoring large composite numbers. The security strength increases with longer key lengths.

  • Established and widely used, it provides robust security if implemented with sufficient key lengths. It is suitable for key exchange, digital signatures, and cryptographic applications.

  • Longer key lengths can impact performance.

ECC (Elliptic Curve Cryptography)

  • ECC provides strong security with shorter key lengths compared to traditional algorithms. Standard key lengths include 256 and 384 bits.

  • ECC is based on the mathematical properties of elliptic curves over finite fields. It offers robust security with shorter key lengths, making it computationally efficient.

  • Strong security with shorter key lengths, leading to better performance. Suitable for resource-constrained environments, such as mobile devices and IoT devices. Increasingly adopted for modern cryptographic applications. Adoption challenges in some legacy systems.

RSA vs ECC:

  1. Key Length: In both RSA and ECC, the security strength is heavily influenced by the length of the key. As computing power increases, longer key lengths are recommended to maintain a high level of security.

  2. Cryptanalysis Advances: The strength of cryptographic algorithms is always subject to potential advances in cryptanalysis. Algorithms once considered secure might become vulnerable with the discovery of new mathematical techniques or computing advancements.

  3. Standards and Recommendations: The strength of cryptographic algorithms is often guided by industry standards and recommendations. Organizations like NIST (National Institute of Standards and Technology) provide cryptographic algorithms and key length guidelines.

  4. Practical Considerations: The choice between RSA and ECC may also depend on practical considerations, such as computational efficiency, key distribution, and compatibility with existing systems.