Barbie typewriter

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Alphabet substitution cipher

Barbie ¹ Typewriter, is a series of electronic typewriters, developed around 1998 by Mehano in Slovenia (ex-Yugoslavia) as a childeren's toy. It was sold worldwide by Mattel (US). The E-118 is the latest model in the product line that started with the E-115. The electronic typewriter was the successor to the earlier purely mechanical Barbie typewriter models. It is little known that most electronic variants have a hidden built-in cryptographic capability that allows secret writing. ²

Although the E-118 is bascially identical to the earlier models, the exterior has changed quite a bit over the years, probably to appeal more to young girls. Furthermore, the interior (especially the PCB) has been simplified several times in order to cut on production cost. Wilst the earlier models were all made at the Mehano factory in Slovenia, the latest one is assembled in China. The E-118 consists of a plastic body with a 49-button keyboard, a plastic carriage that accepts common paper sheets, and a daisy wheel printer. It is aimed at children of 5 years and older.

Wilst the earlier models allowed the machine to be operated on internal batteries or an external mains power supply unit (PSU), the battery compartment was omitted from the later E-117 and E-118 models. The first model was E-115 which was initially sold directly by manufacturer Mehano.

The image on the right shows the initial electronic Mehano typewriter on which all later electronic Barbie typewriters are based. The original version can be recognised by the typical grey colour of the case and the blue-ish knobs. Apart from a range of typesetting features, such as letter-spacing and underline, this children's toy was capable of encoding and decoding secret messages, using one of 4 built-in cipher modes. These modes were activated by entering a special key sequence on the keyboard, and was explained only in the original documentation.

When the E-115 was adopted by Mattel as an addition to the Barbie™ product line, it was aimed mainly at girls with a minimum age of 5 years. For this reason the product was given a pink-and-purple case and the Barbie logo and image were printed on the body. As it was probably thought that secret writing would not appeal to girls, the coding/decoding facilities were omitted from the manual. Nevertheless, these facilities can still be accessed if you know how to activate them.

1. Barbie is a registered trademark of Mattel (USA).
2. Note that encryption is not available on the earlier mechanical typewriters.

Below is an overview of all electronic Barbie Typewriter models that are currently known. In all models, a simple daisy wheel printer is used, consisting of plastic parts, two solenoids and a motor. The electronics are on a small PCB at the center of the unit. In order save on production costs, the microcontroller was directly bonded to the PCB in the later models.

E-115		E-116		E-117		E-118

All electronic Barbie typewriters are based on the initial Mehano E-115 model that was sold directly by Mehano in 1998. This early variant can be recognised by its grey case as shown above. The image on the right shows the Barbie-version of this typewriter with its typical colours. This version contains the first revision of the electronics (revision A), which consists of a well designed PCB with all components on one side, including a 24-pin microcontroller which logo of the Swiss company EM Microelectronic. It is a customised part with a 4-bit microcontroller [5].

Although we have seen at least one E115 that has the hidden encryption capability, we have received reports from readers, that it might not be available on all E115 models and language variants. It would be great if owners of an E115 could confirm this feature.

So far we have not seen the Barbie-variant of the E-116, so we are showing the Mehano-variant instead. It is very similar to the E-115 and has the same case layout. The battery compartment of the E-115 is still present, but can no longer be used as its contacts are missing completely. The image on the right shows the French version of the E-116, on which the crypto features are not available. It is currently unknown whether these features can be unlocked on this version.

Although this version looks different from the one above, it is basically the same machine in a different case. In order to cut costs, the EM microcontroller is now bonded directly to the solder side of the PCB. It is visible as a black 'blob' which can not be replaced. The PCB still shows the tracks that were used for a microcontroller in SMD/QFP packaging,` that could be fitted instead of the direct bonded one. This was probably used in an earlier model (E-116?) or was provided to allow regular chips to be used in case of shortages of bare ones.

This is the latest model that is still being sold today (2015). The design is largely unchanged from the previous one, although the case has been given a more modern shape. In order to reduce costs even further, the units are now built in China and the PCB has received another makeover, probably in order to use cheaper components. The quality of the PCB is visibly lower than with the earlier models. The PCB is now only suitable for a directly bonded microcontroller and several language variants are known.

Although there are many different models and country variants of the Barbie typewriters, and the internal PCB was redesigned a number of times, the encryption/decryption facilities seem to be present on all electronic models. The crypto facilities can be accessed by pressing SHIFT and LOCK in combination with one of the highlighted keys in the diagram below. As the keyboard layout can be different for each country, please use the black numbers as a reference.

The encryption facilities of the Barbie Typewriter consist of a mono alphabet substitution cipher, also known as MASC, with 4 different keys (i.e. 4 different transposed alphabets) which we will call KEY 1 thru 4. When coding a message, the desired KEY is selected with the first 4 buttons on the top row of the keyboard. Note that the black numbers are shown here for clarity only. They are not printed on the keyboard. To start coding, three keys have to be pressed simultaneously:
Once the KEY has been selected, the plaintext message can be entered on the keyboard and the ciphertext message will appear on the paper. The paper may now be sent to the recipient by means of regular mail other otherwise. The recipient should now select the appropriate KEY for decoding by using the corresponding key combination shown below:
Once the KEY for decoding has been selected, the recipient should enter the ciphertext message on the keyboard and, if all goes well, the original plaintext message will appear on the paper. In order to return to normal use of the typewriter, use the following key combination:

For different countries in the worlds, different variants of the typewriters were made. In some cases, this only affected the layout of the keyboard and the printing wheel. In any case, Barbie/Mehano typewriters were made with English, German and French keyboard layouts.

On the foreign version of the E-118, not only the layout of the keyboard was different, but also the firmware. This means that the instructions for coding and decoding (see above), might not be correct for every language variant. German collector karsten Hansky [4] has found a French version of the E-118, which is shown in the image on the right. Although the crypto features were not present on the French variant of the earlier E-116, they are available on this one. Note however that to turn on the first encryption mode, the user needs to press Shift + Lock + 1, and not the leftmost key as suggested.

Furthermore, Karsten confirms that text written on the French variant, can not be decoded on, say, a British variant. The machines are therefore not compatible. A copy of the French operating instructions is available below. In this manual, the cryptographic capabilities are not discussed.

The tables below show the alphabet subsitution tables for each of the four encryption modes of the British version of the E117B, which has a QWERTY keyboard layout. Many thanks to Karsten Hansky for supplying the tables below and the photograph of the British keyboard layout [4].