Is it possible to encrypt with private key using .net RSACryptoServiceProvider?

Question

I know that RSACryptoServiceProvider can encrypt with the public key, then it can be decrypted with the private key.

Is it possible to encrypt with the private key a

Answer 1

EDIT: I should preface this answer by saying that the specific .NET RSACyrptoServiceProvider likely will not support this, due the cargo cult "knowledge" that this is impossible or the more pragmatic knowledge that this is rarely useful to do in practice.

ORIGINAL:

Everyone claiming that there is no such thing either doesn't know how RSA works, or they are stuck in the "signing" rut.

It is entirely possible, and makes complete sense, to encrypt with the private key. Yes, this is similar to signing, but this is NOT at all what most modern libraries take as signing. To them, this means computing a message digest, or HMAC, and encrypting with the private key. Likening encryption with the private key to signing makes just as much sense as saying that sticking a document in a safe, and leaving the key lying around, is a stand-in for signing the document.

Yes, it IS encrypting, because its the same operation. The private-key encrypted ciphertext is just as illegible as the public-key encrypted ciphertext; one needs both keys to decrypt the ciphertext.

See http://fringe.davesource.com/Fringe/Crypt/RSA/Algorithm.html for reference on the RSA algorithm.