"Send the password to given email… in encrypt form" would defeat the purpose of encryption.
This is not how encrypting is done these days. Amazingly enough, to people never familiar to each other and never having any preliminary arrangement can exchange secret messages using open communication line; and even if some person spied on them from the very beginning will not be able to decrypt the messages, even if this person capture all keys transmitted.
Most people try to use logic and make a conclusion that this is impossible. They do a subtle logical mistake which can be fixed if one reads about the idea of
public-key cryptography. It can be understood by reading this:
http://en.wikipedia.org/wiki/Public-key_cryptography[
^].
Just follow the communications between Alice and Bob and you will get the idea.
Such algorithms are also called
asymmetric algorithms.
In turn, this is all based on the idea of
one-way function, see
http://en.wikipedia.org/wiki/One-way_function[
^].
Well-known
RSA algorithm (
http://en.wikipedia.org/wiki/RSA[
^]) is one of the major candidates for a one-way function and is one of the most popular encryption methods. There is a number of others.
Now, this is all well implemented in .NET. See:
http://msdn.microsoft.com/en-us/library/system.security.cryptography.asymmetricalgorithm.aspx[
^],
http://msdn.microsoft.com/en-us/library/system.security.cryptography.aspx[
^].
—SA
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