Sorry,
@Doughnut NZ , but I don't follow. Can you please explain in simple language for computer dummies why not?
All computers talk in binary code and in the beginning, programmers had to load information (data and programs) into the first computers using banks of switches. Information that came out was read from banks of lights. Note that switches can be on and off and the same with lights and so binary code (zero or one) related directly to on and off.
That was a bit tedious, slow and error prone and soon someone invented paper tape and cards with holes punched in them to speed up the process and at about the same time decided that while computers did need to communicate in binary code, humans did not need to do the same.
The early computers had various "word" lengths, a convenient grouping of binary codes. Initially, each computer manufacturer and even different models of computers had different word lengths. They could be grouped in twos, threes, fours, sixs, eights, tens, twelves, sixteens and even twenty-twos. Binary digits were grouped into "words" so that they could
be moved around within the computer using a single action for the word. This greatly sped up computer activity. However, with different word lengths there was no simple and common way of converting binary codes into a more human readable format.
As an example, a group of two binary digits could have four possible combinations. 00; 01; 10; and 11. To make these combinations more readable we could assign them the decimal digits 0; 1; 2 and 3. Similarly, with a grouping (word length) of 3 you could have eight different combinations and these combinations could then be assigned to the decimal digits 0 through 7.
During the early 1960's International Business Machines (IBM) was the dominant computer manufacturer and in 1963 they introduced a very successful range of computers that used 8 binary digit (also called 8 bits) bytes, with 4 bytes per word, giving a 32 bit word. This was the IBM System 360 range of computers.
Alongside the System 360 IBM introduced Extended Binary Coded Decimal Interchange Code (EBCDIC) and hexadecimal (base 16) number representation using the decimal digits 0 through 9 and A through F for the other 6 "digits".
As an aside, IBM wasn't the first computer company to use hexadecimal coded numbers in computers. Another company beat them to it but used u through z instead of A through F for the digits above 9. However, IBM's system won out and today the A to F representation is used almost universally.
Also base16 numbers (hexadecimal numbers) existed before IBM used them in their computers but IBM was the second (and dominant) computer manufacturer to use them. There is some disagreement about who first invented base16 number systems, some attribute it to a French wizard with eight fingers on each hand and others to a Swedish mathematician, see Wikipedia.
Hexadecimal numbers fit computers very well. It takes 4 bits (0000 through 1111) and so significantly shortens (and simplifies) computer input and output while also being a multiple of the 32 bit word used in the System 360. For example, 8BADF00D is much simpler (for humans) and more compact than 10001011101011011111000000001101.
Typically, hexadecimal numbers are written as couplets and so 8BADF00D would typically be written as 8B AD F0 0D.
Okay, that was a very long winded and perhaps interesting explanation of what hex(adecimal) numbers are but why did I react so strongly when I saw the WiFi password that was shown by the original poster?
Well, because hex numbers are so universal across computers and so close to the binary code that computers understand that it is possible for someone who knows what they are doing to write a program using just hexadecimal numbers. Bad operators (i.e. hackers) can use hexadecimal numbers and buffer overload vulnerabilities to do bad things to other people's computer devices.
Here is a very simple program fragment written in a random Assembler language (don't ask):
LDA A 80 04
ASR A
BCC FA
LDA A 80 05
AND A 7F
JMP C0 79
Here is the hexadecimal numbers produced by the Assembler that is capable of running on the computer that the assembly language is designed for:
B680044724FAB68005847F7EC079
If I enter this string into an input field that is vulnerable to buffer overflow on a computer that uses these operators then this program could run!
There were other long and complex WiFi passwords shown in later posts on this topic that are NOT made up of hexadecimal numbers. These other passwords are not a problem, just the first one posted.
As far as I am aware, NO manufacturer uses hexadecimal numbers for the default WiFi password.
