NCrypt TX Frequently Asked Questions
(FAQ)

I need to send encrypted messages by e-mail. How can I do that with NCrypt?

You can use your favorite editor or e-mail program to compose the message.

When you have finished just "cut" (CTRL+X) the message e "paste" (CTRL+V) it into an open window of NCrypt TX.

Select your password and/or shift, the encryption algorithm and press the "Crypt" button (to the left).

Now, your message has been encrypted.

You can now "copy" (CTRL+C) it and "paste" (CTRL+V) it again in your e-mail program, and you're ready to send it. You can also select all of your text and copy it with a single shortcut: CTRL+A.

I need to decrypt an encrypted message I received from a friend who is using NCrypt. How can I do that?

When you received an encrypted message, it will probably look like this:

2A 6E 3B 4F 3F 31 5E 34 45 20 20 27 4D 61 2D 50 2B 5B 29 2E 3F 20 22 4F EC 3B 57 33 58 75 2F 5E 3C 44 23 2C 27 27 A1 20 5B 49 53 70 20 54 33 76 6E 57 77 74 E0 37 E9 F2 42 2F E9 76 2B 22 3E 0A 2A F2 74 51 7A 3E 0A 62 F2 B0 30 64 6A 0A 62 7C 69 74 B0 7A 3E 63 51 72 41 38 35 60 3B 6F 4D 21 34 26 61 64 23 2E 61 4B 73 3C 75 43 E0 43 42 65 6A 0A 62 25 65 74 76 23 68 58 E7 70 64 B0 32 44 38 76 73 22 5D 26 6E 74 7A E9 74 A7 3C 79 31 B0 22 60 32 6F 44 25 B0 5E 74 3D 22 35 65 7D E7 2F F2 43 E7 34 6E 20 32 3A F2

In order to decipher it, you must copy and paste it into an open NCrypt TX window.

You must know:

•  The algorithm that was used to encrypt it
•  The passphrase or password
•  Eventually, the shift (only a few algorithms need a shift)

Then you can press the Decrypt button to see the message in clear.

I need to know if my encrypted message was correctly received, that is, if all of the characters composing the message were transmitted correctly over the Internet, or if they were correctly delivered to the message recipient.

When you encrypt a message, just one character badly sent from the sender to the recipient can make the decryption fail.

In order to avoid that, you can send, along with the message, the "fingerprint" of the original message and/or of the encrypted message.

The "fingerprint" is a unique series of bytes that identify a message.

You can obtain a "fingerprint" of your message by pressing the "Hash" button, and then enclose the hash with your message.

The recipient can do the same, and by confronting his result with the given one, establish if the message has been tampered/broken during the transmission.

How can I confront the hash of my text/encrypted message with the sender's one?

If the sender sent the hash string along with the message, you can verify the integrity by pasting the received hash in the "Verify Hash" window.

NCrypt TX will compute the hash of your current message and confront it with the supplied hash. If the two are equal, the original message is completely equal to the one you currently have in the editor window.

I encrypted a message with NCrypt. How can I communicate to the recipient which algorithm and passphrase I used?

This is the principal problem of the symmetric encryption. NCrypt TX supports only "symmetric" encryption, which means that the way by which the key is sent between the sender and the recipient is NOT SPECIFIED.

Plus, the same key encrypts and decrypts the message.

If you need to send the key along with your message and being secure that the key will not be intercepted, you must make use of an "asymmetric" tool, also known as "public key" encryption tool. One is GNUpg.

Public key tools are not so easy to use. Besides, most of times you won't need the complexity of an asymmetric tools to secure your messages.

In order to achieve an acceptable level of security, you must

•  Select a strong algorithm (DES or Rijndael are perfect for this)
•  Communicate the passphrase (or key, or password) over a different channel

The second point means that if your encrypted message is sent over the Internet (with an e-mail, for instance), it is not a good idea to send another email in which you tell about the algorithm and password you used for the encryption.

Using another channel means: telling your recipient the password by voice, or by letter. Changing the channel implies that the person who will be able to break your code will be as well able to intercept the first channel (the voice, the phone call, the letter) and the second one (the e-mail through Internet).

Also, you can establish a passphrase pattern in order to change the passphrase without the need to communicate it.

Suppose that John must send encrypted messages to Mary all over one year. The goal is to change the passphrase every month, without communicate it every time.

John and Mary meets in a solitary place. John says to Mary that he will use NCrypt with algorithm DES and a passphrase pattern.

The pattern he chooses is "current month"+"first word on the n page of the Gone with the wind novel" where n is the day of the month in which the message was sent, all lowercase.

So, if the message was sent on April 13, the password is aprilrather (rather is the first word on page 13 of the novel).

As you can see, there's no limit to imagination.

I received an encrypted message made of hexadecimal numbers. I opened it with NCrypt. I set the passphrase, shift and algorithm with the correct values, but when I press the Decrypt button I obtain nothing but meaningless characters?

Have you set the "Hex" option?

When you receive a message made by hexadecimal numbers, you must set "Hex" in order to decrypt it.

If the used algorithm is Rijndael or TripleDES, make sure you set the correct size of key and/or block. To adjust them, select Action/Options menu item.

I do not want to set a passphrase. Is there an algorithm that can work without it?

If both the sender and the receiver use NCrypt TX and they are confident that no other can even think to use NCrypt TX to decrypt the message, then they make use of the Playfair algorithm.

Even if Playfair is a standard, historical algorithm, the specific implementation of it in NCrypt TX makes of it the only tool on Earth to decrypt a message encrypted in such a way.

Is it true that Playfair algorithm works only with texts that have an even number of characters?

Why isn't NCrypt TX integrated with my e-mail client?

Opening and arranging e-mail messages from another application is considered harmful and it is contrary to most companies' software policies. A program that is able to send e-mail messages with attachments is considered - with reason - malware.

NCrypt TX is a fair application that does nothing potentially harmful for any user. We think the user is free to decide how to send encrypted messages via e-mail in the way he/she prefers. Nonetheless we offer a "Send via e-mail" command, which will transfer the encrypted or decrypted message to your favorite e-mail program.