RSA encryption - How to encrypt to smaller size than key

Question

I use RSA encryption in my project, and I need to encrypt array of bytes to encrypted array of bytes, that his length is smaller than the key length (I use 2048 bit key). When I use the RSACryptoServiceProvider class with c# it always encrypt it to an array of bytes that his length is the key length (256 bytes). I know I cannot encrypt it to a longer size than the key, but, can I encrypt it to a smaller one (to the originial non-encrypted array of bytes length)?

Answer 1

不能。在进行加密之前，必须对明文填充密钥大小，以防止某些类型的密码分析攻击，因此，对于RSA实现（ 尤其是那些打算用于一般用途的实现），忽略它是没有意义的。