Email Encryption End-to-End
Hermetic Systems

German version

Email encryption has become a hot topic since the revelations by Edward Snowden in mid-2014 that the NSA gobbles up every email message you send, then sifts through them to ascertain whether they contain something worth examining more closely (such as your business plans), or even whether you might be a person of interest to some other 3-letter agencies. But most people believe (partly rightly so) that email encryption is difficult. It doesn't have to be. This software is very easy to use (but nevertheless provides strong encryption). Here is a sample screenshot just prior to encrypting a message:

Download the
trial version
a user license
Translate to:

Email Encryption End-to-End screenshot #1

Email Encryption End-to-End makes it easy to send and receive encrypted email. It can be used to encrypt a message to be sent via any desktop email program or webmail that supports attachments (files attached to a message). The encrypted message consists of a text message (up to 60 KB in size) plus, optionally, an appended file of any type (up to 1,980 KB = 1.93 MB in size). The message (including any appended file) is encrypted, and is attached to an ordinary email message, before it leaves your PC to go to the mail server, and it remains encrypted during transmission to the recipient's ISP and while being downloaded to the recipient's PC. Thus the message is encrypted "end-to-end", and, if intercepted anywhere between your PC and the recipient's PC, cannot be read.

AT&T provided National Security Agency eavesdroppers with full access to its customers' phone calls, and shunted its customers' internet traffic to data-mining equipment installed in a secret room in its San Francisco switching center, according to a former AT&T worker cooperating in the Electronic Frontier Foundation's lawsuit against the company.Ryan Singel (Wired): Whistle-Blower Outs NSA Spy Room  (See also.)

Data mining yields no results from encrypted files.

The National Security Agency has obtained direct access to the systems of Google, Facebook, Apple and other US internet giants, according to a top secret document obtained by the Guardian. The NSA access is part of a previously undisclosed program called PRISM, which allows officials to collect material including search history, the content of emails, file transfers and live chats, the document says.Glenn Greenwald and Ewen MacAskill (UK Guardian): NSA Prism program taps in to user data of Apple, Google and others

So it's not just "metadata" (time, location, etc.); the NSA can actually read the content of your email messages — except, of course, that part of the content which is encrypted. You could use PGP, but PGP is complicated and time-consuming. This program (EEE) is simple, quick and secure. It has no 'backdoor', and the encryption key is not hidden in the ciphertext. This software was developed to be as secure as possible, with no collaboration at any time with any government agency in any country.

In an online interview (via The Guardian) Edward Snowden said: "Encryption works. Properly implemented strong crypto systems are one of the few things that you can rely on. Unfortunately, endpoint security is so terrifically weak that NSA can frequently find ways around it." EEE is designed for strong "endpoint security".

Note that this program cannot be used to send EEE-encrypted messages to a gmail account, because (surprisingly!) all messages received with an attached 'zip' file are automatically blocked.

Use of the Program
Specifying the Encryption Key
Comparing Plaintext and Ciphertext for Randomness
How to Test the Trial Version
The Encryption Method
  Compatible with Windows 7 and Windows 8
See also: A Practical Example of the Use of Email Encryption End-to-End

Use of the Program

The message can be composed in the text box or a pre-written message can be loaded from a text file. You can (though you don't have to) append a file of any type (in this example, a ZIP file containing six documents, ''): click on the 'Append file' button and select the file in the usual way.

The program creates an output file (the ciphertext file) containing the encrypted message plus the encrypted appended file (if any). This file always has a 'zip' extension, but it is not a ZIP file. You have to specify a folder where this file will be located, and a name for the file (the extension 'zip' will be added automatically).

Then clicking on the button 'Encrypt message and write it to ciphertext file' creates the output file (this normally requires anything from a few seconds to a minute), after which the message at right is displayed.

Then compose an ordinary email message to your colleague (using any email program or webmail client which supports email attachments), something like:

Further to our recent conversation concerning our construction project, attached is the document ( with the guidelines for making the required application to the relevant government department. Please pass it on to your legal team for their comment.

Attach the file created by Email Encryption End-to-End (EEE) — in this example, the file '' (which is not a real ZIP file but is the ciphertext file produced by EEE) — and send the message.

If the recipient is expecting a message with an attached ciphertext file then there's no need to refer to it in the 'cover message'. Just compose some message about the weather, the price of gold or whatever (but nothing of possible interest to any eavesdropper), attach the ciphertext file and send the message.

When your colleague receives this message in his email client he notes that it has an attached file, and saves that file to any convenient location. Since it (always) has a 'zip' extension he might be tempted to run an unzip program, but instead he should run EEE, select 'Decrypt message received' and tell the program where to find the ciphertext file (in this example the file ''). To decrypt the message he must know the key which you used to encrypt it. When EEE decrypts the ciphertext file it displays your message ("Since these days ..."). If it finds that there is an attached part (as in this example), it asks your colleague for the location of a folder in which to save it.

Email Encryption End-to-End screenshot #2

EEE then saves it in that folder, with the original name. Your colleague can then view the file which you sent (or if it is, say, an Excel spreadsheet or some other kind of file he can open it with the appropriate program).

If the message you sent is intercepted somewhere between your PC and your colleague's PC an eavesdropper will see only a message about a document with government guidelines or a comment on the weather or whatever, plus an attached 'zip' file which the eavesdropper is unable to open.

After the ciphertext file has been created, it can be renamed. The decryption process does not depend on the particular name used when creating the file in EEE.

Specifying the Encryption Key

Email Encryption End-to-End uses a symmetric key encryption method, meaning that when a message is encrypted, the key required for decryption is the same as the key that was used for encyption (so "key" on this page may mean either "encryption key" or "decryption key", since they are the same).

To specify a key click on the 'Key' button and a window will appear which enables you to enter the key:

encryption key

No distinction is made between upper case letters and lower case, and spaces are ignored, so "Pass Word" is equivalent to "password". Keys may include non-English characters, e.g., "je rêve des chèvres françaises".

The longer the key the more secure it is. So it is advisable to use a key which is based upon some phrase that you can easily remember, but modified in some way (as in the example above) so that the key is not simply the phrase itself (which would make the key vulnerable to a 'dictionary attack').

Since the key in the example above includes words found in a dictionary, one might prefer to use a phrase with words broken in a way easy to remember, something like:

another encryption key

As you type the key a checksum is calculated and is displayed. If you use a key more than once then it is advisable to remember the final checksum. After entering a key an unusual checksum will show that a typing error was made. Failing to notice a typo when decrypting has no fatal consequences (you simply get an error message), but if you mistype the key prior to encrypting then the encrypted message cannot be decrypted using the intended key.

For the recipient of an encrypted message to be able to decrypt it, they must know the key, which must be communicated somehow. The way this is done depends on the level of security needed. You can simply phone the recipient and tell them the key. Sending the key by post is slower but perhaps more secure. Best is to meet the intended recipient in person and tell them or pass a note. If a meeting is not possible then a key can sometimes be agreed upon by referring to some item of information from your common past (e.g., the name of the restaurant where you used to have lunch together years ago). If you have never met, but have exchanged email then you can use the first few words from some email message (the older the better) which you have both kept.

Comparing Plaintext and Ciphertext for Randomness

Plaintext (even in compressed files) always exhibits some degree of non-randomness. An insecure encryption method will produce ciphertext which is more or less non-random, and this non-randomness can help an attacker to decrypt the ciphertext without knowing the encryption key.

Randomness buttonEmail Encryption End-to-End produces highly random ciphertext. After encrypting a message (and optionally an appended file) the button shown at right is enabled. Clicking on this will produce a window which graphically illustrates the randomness in the plaintext compared to randomness in the ciphertext. When the plaintext is mostly a ZIP file there is not much difference. But when the plaintext is entirely natural language text or a docx file then the difference is great, as illustrted below:

The randomness graphic is produced as follows: Each pair of bytes in a block of data is considered successively. Byte values range from 0 through 255. The first byte value is halved and is used as the x-coordinate in the 128x128 graphic, and the second byte value is halved and used as the y-coordinate, then a pixel is plotted at that x-y position in the picture. When the bytes have values which appear random then the pixels will be plotted at apparently random positions. When the byte values are not random (which is especially the case in data consisting only of text) non-randomness will be evident.

The "randomness measure" can range from near-zero to near-one, with a higher value indicating a higher degree of randomness.

How to Test the Trial Version

You can download a trial version of Email Encryption End-to-End (EEE) from this website. This can be used for 30 days from the date of installation to encrypt messages, after which it can no longer be used to do that (but can still be used to decrypt messages). The encryption key in the trial version may be of any length from 16 to 64 characters, but must consist only of a single character repeated, optionally with spaces. (Any key may be used for decryption.) Thus messages encrypted using the trial version are insecure because the key used is from a very limited set, and so a brute force method can be used for unauthorized decryption.

To test the trial version, firstly run EEE and compose a message in the textbox, then encrypt it to a ciphertext file, say ''. In your email client create some message and then attach Send the message either to yourself (using the same or a different email address). When you receive the message, save the attached file (''). Run EEE, tell it where to find, and decrypt the message using the same key. Then compare the message sent with the message received. You could also exchange encrypted messages with a friend (who has also downloaded the trial version) if you tell them the key you use.

Secondly, do the same, but this time append some file. When you (or your friend) receives the message, and EEE discovers that it has an appended file, tell the program where to save it (but not in the same folder as the file that you appended before sending, since it will be saved with the original name). Then compare the file sent with the file received.

The Encryption Method

Email Encryption End-to-End uses the encryption algorithm as used by our earlier cryptographic product, Cryptosystem ME6. This encryption method is described in The Cryptosystem ME6 Encryption Process. Cryptosystem ME6 was developed in Europe, was first released in 2001, and has been used continually since then, during which time no weakness in the encryption method has been discovered.

A secure encryption method can be broken only by a brute force attack, that is, by trying every possible key. Whether this is feasible depends on (i) how quickly keys can be tested and (ii) how many keys have to be tested. Keys used with Email Encryption End-to-End consist of characters which can be typed at the keyboard (with no distinction between upper and lower case). There are 26 letters, 10 digits and (let's say) 28 punctuation and other characters, for a total of 64 typeable characters. The key can consist of up to 64 characters, but keys longer than, say, 32 characters are unlikely. If we consider only keys of not more than 32 characters, then the number of possible keys is 64^32, which equals 2^192. Thus it is reasonable to assert that Email Encryption End-to-End has in practice something like a 192-bit keyspace.

Since 64^32 is approximately 10^57, if a billion billion billion keys (10^27) could be tested each second then it would still take approximately a million million (10^12) times the estimated age of the universe (some 14 billion years) to test all possible keys. Email Encryption End-to-End can thus be considered secure against a brute force attack.

Here is a good article on this subject by Gary Smith:
Email Encryption — A Security System for Today's Wired World
See also German Firms Race to Shield Secrets
and The Encryption Debate is Really About How Best to Spy on You

Here is download3k's review of this software: Email Encryption End-to-End 10.01

Virus-free Trial version: A trial version of Email Encryption End-to-End can be downloaded from this website. Click on the link below to go to a web page with further information:

Download Email Encryption End-to-End ...

Click here to see prices.
Price and ordering: A single-user license for the fully-functional software is available for a period of 3 months, 1 year or with no time limit (a 'perpetual' license). Prices for each type of license are given at Purchase a User License. (A multiple-user license is available for this program.) An activation key is required in order to make the trial version permanently fully functional. An activation key can be obtained immediately if you purchase a user license either via PayPal or via Share-it.

Refund: A refund will be provided promptly up to 30 days after purchase if the software does not perform satisfactorily.

Updates: Purchasers of a user license for this software are entitled to an update to any later version at no additional cost.

Hermetic Systems Home Page