RSA block by block encryption produces blank output for files larger than 1kb

Question

I\'m not opening this thread for AES or other encryptions because this is what I\'m going to use to encrypt the keys of AES and other encryptions. I\'ve gathered several codes f

Answer 1

RSA is not ment for bulk encryption as it's quit slow compared to symmetric algorithms like AES (it's more than a factor of 1000 slower). The amount of data that can be encrypted with RSA in one block is dependent on the key size and any data that might be used by padding.

When you need the two keys of RSA and at the same time need to encrypt more than what can be in one RSA block, you would usually use Hybrid encryption, where you encrypt the data part with a random symmetric key, and then encrypt the encryption key with RSA. This way you get the speed of the symmetric key, and the two keys of the RSA. But if you don't really need to have different keys for encryption and decryption then you properly should not use RSA at all.

As RSA is not ment for bulk encryption, the standard implementation's can't handle it when you try to encrypt more than what can be in one block - no logic is implemented for chaining of encryption blocks with RSA. This would be handle for symmetric ciphers out of the box.