proxy_recrypt 1.1.4

Proxy Re-Encryption (PRE) utilities for Dart enabling secure, server-mediated sharing of encrypted data without exposing plaintext.

recrypt

Proxy Re-Encryption (PRE) utilities for Dart enabling secure, server-mediated sharing of encrypted data without exposing plaintext. This library lets a data owner encrypt content once, then delegate decryption rights to other parties via transformation (re-encryption) keys—without sharing private keys or re-encrypting the original data.

Use cases:

• End-to-end encrypted group or multi-recipient messaging
• Zero-knowledge relay / brokered data exchange
• Secure access delegation and revocation Core concepts:
• Owner encrypts a symmetric content key under their public key
• A transformation key (owner private key + recipient public key) lets an untrusted server convert the encrypted key for a recipient
• Recipient uses their private key to recover the symmetric key and decrypt the content
• Server never learns the plaintext or symmetric key

Benefits:

• Least-privilege server role
• Scales better than encrypting separately for every recipient
• Cryptographic separation of duties (encryption, transformation, decryption)
• Ideal when you need brokered delivery (e.g. group chat) where the transport service must route but not read messages.

Attribution

This Dart implementation was inspired by the original JavaScript proxy re-encryption implementation available at:

• JavaScript PRE Implementation
• Proxy Script

We acknowledge and appreciate the foundational work that guided our Dart port.