The National Intelligence Organization (MİT) has shared a historical document with the public concerning the deciphering of secret correspondence prepared with the phrase "to be opened personally".

The document was published in the "Documents" section under the "Special Collection" tab on MİT's official website. Thus, a new example was added to intelligence reports.

The published document is dated August 27, 1933. It serves as an example of the envelope opening/closing and secret writing deciphering activities of the D (Technical Support) Branch affiliated with the Presidency of National Security Service (MAH). The document contains a letter sent to the Istanbul B Directorate with the phrase "to be opened personally".

The statements recorded in the document are as follows:

"The letter received in mailbox number 230 and sent to the Presidency to be opened was opened using the method described in the note obtained from D. branch. Since an experiment was conducted on the first page of this two-page letter, the writings have partially disappeared. The meanings of the words in the readable part and the translation of the second page have been sent as an attachment. Since the signature 'Lüsi' is found in the letter translated here, it is probable that the letter's owner is Lucci Vidman. If it becomes necessary to apply chemical treatment to letters received from this box hereafter, please use the following formula."

In the note section of the document, it is detailed how secret letters and correspondence should be opened. According to this, it is stated that a mixture of 10 grams of perchlorure de fer (iron chloride) and 90 grams of maimukattar (distilled water) should be used.

The note states that the obtained solution should be placed in a tray and the paper should be bathed like photographic paper. It is also added that applying it with a brush will not yield good results.