3 ms·
This doesn't work for encryption, though. You'd need a cryptosystem where it's possible to encrypt a message with H(x) such that it can only (efficiently) be de
by atq2119 7y ago
This doesn't work for encryption, though. You'd need a cryptosystem where it's possible to encrypt a message with H(x) such that it can only (efficiently) be decrypted given x, for a hash function H. To the best of my knowledge, no such hash function is known.
- EGreg 7y agoIt’s an open question whether hash functions can be used for encryption using XOR: https://crypto.stackexchange.com/questions/35809/whats-wrong-with-xor-encryption-with-hash-and-an-iterated-salt https://crypto.stackexchange.com/questions/35809/whats-wrong... Here is a basic explanation: https://cryptography.fandom.com/wiki/Snuffle https://cryptography.fandom.com/wiki/Snuffle Note however that you would need a nonce / salt transmitted with each message because otherwise decrypting messages encrypted with the same key would just be as easy as XORing them!
- atq2119 7y agoSnuffle is symmetric key encryption, and yes, it's a well-known construction. However, you previously suggested that an asymmetric encryption scheme (with public and private keys) could be constructed using a hash.
- EGreg 7y agooh, right. It’s only good for signing and random number generation, not encryption. Still that’s plenty useful! It can be used for blockchains and crypto currency.