I need to encrypt a high number of short messages (30-200 bytes). The problem with usual algorithms, such as RSA, is that the size of the encrypted message tends to increase a lot, compared to symmetric encryption algorithms.
Ideally, this cryptosystem shoud accomplish:
- Size of the encrypted message must be at most 25% longer than the original
- Should be fast encryption and decryption
- It's not a problem if, after some work, some messages are decrypted
- But private key must not be found so easily
- It would ve good if it's a known algorithm with solid implementations in most common languages
The only solution I found until now is using RSA with short keys (64 bits), but I wonder what a better approach could be.