Every day Lee and Helen had an hour to walk by the sea, but the escorts were inseparable on each walk, and they were staggered, so they didn't have time to meet.

But Helen used a special footprint to step on a heart shape on the beach, and Lee noticed it as he walked, and the heart was on the edge of the rising tide, just enough to touch but not washed away, dancing on the critical line.

The heart shape is not completely closed, and is exactly a toe distance at the beginning and end points. Finally, draw a Cupid's arrow, which is the Caesar's shift coded code agreed upon by the two of them.

The Thai policewoman who followed her didn't understand, and thought it was a woman's unique way of expressing her feelings. "The Gallic Wars" is a reportage written by Gaius Julius Caesar in ancient Rome, and it is a reflection of what he did about his own work

The "plain" record, published in 51 B.C.E. Caesar's Gallic Wars is divided into eight volumes, the first seven of which were written by Caesar, and recount the history until the autumn of 52 BC, and one of Caesar's lieutenants, Hitius, wrote an eighth book for the book, recounting the war until 50 BC.

Caesar describes in the Gallic Wars that he used a cipher to transmit information, which is what later generations called

The "Caesar Code" is an alternative cipher that encrypts the letters by pushing them back 3 digits in order, such as replacing the letter A with the letter D and the letter B with the letter E.

In translocation, the letters do not change, and the position changes; The letter in the substitution changes, and the position remains the same. This password replacement is often referred to as the Caesar shift password.

By simply rearranging the order of the 26 letters of the cipher table and allowing the cipher table to be any kind of rearrangement of the explicit table, the keys will increase to more than 400 trillion yuan, and more than 4×1027 kinds of cipher tables can be obtained.

Cryptography can be broadly divided into two types, displacement and replacement, but there are also more complex methods that combine the two.

In translocation, the letters do not change, and the position changes; The letter in the substitution changes, and the position remains the same. The first documented use of replacement ciphers for military purposes was Caesar's Book of Gaul.

Caesar described how he sent secret letters to Cicero, who was under siege and on the verge of surrender. The Roman alphabet was replaced with the Greek alphabet, making it impossible for the enemy to read the message at all.

In his biography of Caesar in the second century C.E., Sutonius gives a detailed account of one of the alternative ciphers used by Caesar.

Caesar simply replaced each letter of the message with the third letter of the alphabet after that letter.

This password replacement is often referred to as the Caesar shift code, or simply, the Caesar code. Although Sutonius only mentions Caesar shifts in three positions, it is clear that shifts from 1 to 25 positions can be used, so in order to make the password more secure, a single-letter replacement password appears.

Later, after continuous improvement and improvement, people invented the ECC elliptic encryption algorithm and RCC dynamic password password, and later appeared the widely circulated Morse code, which are the core secrets of important fields such as war and intelligence.

Through mental arithmetic, Lee understood what Helen meant. The two of them had already prepared several sets of plans, and Lee made trouble first tonight, making the Thai side think that it was covering Helen's escape, but in fact, it was Lee who really escaped.

But the only thing they don't know for sure is whether the stupid Thai side will be able to adapt to their intelligence.