Video Summary
The video discusses the concept of malleable encryption, highlighting its potential dangers and practical applications. It outlines how attackers can exploit malleable encryption and presents examples including the one-time pad, stream ciphers, and homomorphic encryption such as RSA.
Key Points
- Malleable Encryption: Defined as encryption that allows an attacker to alter the ciphertext, thereby manipulating the plaintext upon decryption.
- One-Time Pad: Considered a perfect encryption method; however, it is malleable because an attacker can still change bits in the ciphertext.
- Stream Ciphers: Use a pseudo-random bit string for encryption, which can also be susceptible to malleability attacks.
- Example of Attack: An attacker can intercept an encrypted password, alter the target website address, and still send the modified ciphertext without knowing the decryption key.
- Homomorphic Encryption: Enables operations on ciphertexts to yield results equivalent to operations on the original plaintexts. Examples include RSA.
- RSA Vulnerability: Allows malicious users to modify bids in auctions by multiplying ciphertexts without decrypting them.
- Voting Example (Non-Secure): Demonstrates using homomorphic encryption for tallying votes but highlights the lack of confidentiality with deterministic encryption, especially within RSA.
- Alternative Schemes: Other cryptosystems like ElGamal and Paillier can offer more security compared to RSA in homomorphic voting schemes.
Youtube Video: https://www.youtube.com/watch?v=40xanXXsw24
Youtube Channel: Computerphile
Video Published: 2024-11-06T10:45:00+00:00