What is Proxy Re encryption?

Understanding Proxy Re encryption

Proxy Re-encryption (PRE) solves a fundamental problem in secure data sharing—how to allow a third party (the proxy) to transform encrypted data from one encryption key to another without ever accessing the unencrypted content or the private keys. This cryptographic approach enables secure delegation scenarios that were previously impractical: cloud providers can transform data encrypted by one user to be accessible by another without gaining access themselves, healthcare providers can securely share encrypted patient records with specialists, and secure messaging platforms can deliver encrypted content to new devices without compromising end-to-end encryption. Unlike traditional approaches requiring either sharing private keys (compromising security) or decrypting and re-encrypting data (exposing content), PRE maintains both security and privacy through specialized mathematical transformations. Implementation typically involves three phases: the data owner generates a re-encryption key for the intended recipient, the proxy uses this key to transform the ciphertext, and finally the recipient decrypts the transformed data with their own private key. Organizations implementing PRE should carefully evaluate algorithm properties like directionality, atomicity, and performance for their specific use cases.