The history of secrecy: From ancient encryption techniques to modern cryptographic methods
Those who write books usually have the goal of reading, understanding and disseminating their content. This is the basic concern of an author: sharing knowledge, thoughts and stories with others. But there are also texts in which the authors intend exactly the opposite. You absolutely want to avoid falling into the wrong hands or unauthorizedto be read. Such texts are found above all in areas where secrecy is of the utmost importance – for example in military, political or secret service communication channels. For these sensitive areas, it is essential to protect the content from unauthorized access. Cryptographic methods were developed to encrypt information in ancient timesand thus make it unreadable for third parties. These early procedures were the foundations of what we know and develop as cryptography today.
Antique secret writings: The use of cryptography in ancient high cultures
The first forms of secret scripture were used in ancient Mesopotamia, Egypt and ancient Greece. The Egyptians used special hieroglyphs, especially in texts related to gods. This was a kind of religious encryption because the pronunciation of the gods’ names was taboo. It was forbidden to loudly pronounce the names of the gods,which is why special hieroglyphs were used to cover them up. In Babylonia, around 1500 BC, secrecy of certain information was just as important. For example, the recipe for a special ceramic glaze was considered extremely valuable – so valuable that it was wanted to protect it from industrial espionage. The Babylonians used a secret script in whichCunerment characters were replaced by others after a designated pattern. This meant that the original characters were replaced by symbols or codes to hide the information from unauthorized access. It is not surprising that in ancient Greece the Spartans were among the pioneers of cryptography, as they preserve a variety of military secretshad. Around 500 BC they developed the so-called Skytale, a simple but effective encryption bar. The scribe spirally wrapped a strip of leather or parchment around the rod with a fixed diameter to write the message. The recipient had a Skytale of the same dimensions and was able to read the message by re-circulating the stripwrapped the rod. However, if the courier was stopped, the opponents only had the strip with the encrypted letters arranged in arbitrary order. It is believed that the Spartan general Lysander, who defeated the Athenians at Aigospotamoi in 405 BC, with the help of the Persians, through such a method of the Persian Satrapene Pharnabazoshould have experienced. This early form of encryption thus effectively saved military secrets from the enemies.
The development of encryption: From substitution to Caesar cipher
A well-known and still famous cryptographic method is the so-called Caesar cipher, named after the Roman general Gaius Julius Caesar. This is said to have used a simple but still effective procedure to encrypt his letters if he wanted to send personal or sensitive messages. In this procedure, the letters of the alphabet arereplaced by other letters in a fixed key. Caesar moved the letters of the alphabet by a certain number of digits – for example, by three. Here, an A becomes a D, a B becomes an E, a C becomes a F and so on. This procedure, also known as a shift ship, is relatively simple, but can be cracked by clever methods. To the encryption yetTo make Caesar safer, the reference alphabet rotated, so shifted so that the same pattern does not always apply. If the three positions are shifted, the A corresponds to the D, but if the alphabet is rotated around the last letters, the A would correspond to a W, for example. Augustus, the first Roman emperor, also used a similar procedure for encryptionhis messages. Caesar, however, was more variable in handling the shift, making the method harder to crack.
Early manuals and decryption: Cryptography in Ancient Rome
Gellius reports, for example, that the Roman grammarian Probus wrote a handbook on cryptography that may contain references to encryption techniques. Caesar’s substitution process is comparatively easy to decipher when analyzing the frequency of the letters in the text. In German, for example, the E is the most common letter, followed by N, R and S.Such frequency analyzes allow the encryption key to be recognized relatively quickly. However, it is unclear whether this method was already known in Caesar’s time or was used by the Arabs to decrypt encrypted texts. It remains an open question whether such techniques were distributed internationally at an early stage or were developed later.
Secret communication: From conspirator groups to Tironian shorthand
Already in ancient times, conspirator groups used coded messages to cover up their internal plans. Thus, in 63 BC, the conspiracy group around Catilina was known to use encrypted messages to hide their secrets from the authorities. Cicero, who then acted as a Roman consul, eventually exposed the group through a combination ofinvestigations and the searching of the codes. He presented a message in the Senate that co-conspirator Publius Cornelius Lentulus Sura had delivered. It is likely that this message was encrypted to protect the content from unauthorized access. Cicero himself did not use a secret type, but a special shorthand, the so-called “Tironic notation”. This becameDeveloped by his slave and secretary Tiro, and included about 4000 characters to stenography of speeches and texts. Tiro even taught senators in this shorthand system, which was a premiere. For example, the speech of the younger Cato was stenographed on the occasion of the first Catilinary conspiracy in 65 BC. Some of the characters in this text are still todaypreserved, including the symbol for “and”, the Latin “&”. This shows that a wide range of strategies for encryption and quick writing of texts were developed in ancient times, some of which have survived to this day.
