New Year's zip quest 2012 - the passage
So, since the launch of the quest, enough time has passed, I post the passage and some answers to the “criticism”. In general, there are much more positive reviews than negative ones. After solving the last riddle, it was suggested to inform me about the passage of the quest. This was done by about 10 people. How many people downloaded the file - I do not know.
Let me remind you that the default password is a number, and guess what kind of a number you can always, without getting into the deep jungle of ambiguities (as some participants thought). In addition, I warned in advance that participants should be a little familiar with programming.
')
Level 1. A pdf document is proposed with a narration about the determinant of a 2x2 matrix and about raising it to the fifth degree. There is no point here, but you can pay attention to the bold letters that make up the word mcmxlviii, which is very similar to writing a number in Roman notation. This number is 1948, it is a password.
Level 2. Of course, you can interpret the file of spaces and stars as you like. But how should a person who is looking for hidden information in a file reason? He will definitely check if there are any hidden characters that are not immediately visible. Take any normal hex-viewer and open the file in it, immediately seeing a 2x2 matrix consisting of numbers 4 7 1 8 in the simplified ASCII-art style. You might think that the answer is the number 4718 or some other 23 numbers that can be obtained from these numbers. But this is a wrong train of thought, since it leads to ambiguities, but it is believed that there are none. You do not think that I wrote the text about the determinant in the fifth degree on the previous level for nothing? The determinant is 25, and in the fifth degree it will be equal to 9765625.
Level 3. In this level hint. It should be clear that md5 hashes are written out. The first 6 of them have types that are easy to find on the Internet. They form the expression “use your brain and chromosomal crossover”. The following 2 hashes cannot be decrypted. Next, you need to look at what “chromosomal crossover” is and guess that the md5 hashes were split in half, and then the first half of the first hash is connected to the second half of the second and vice versa. Having done the reverse operation, you will find that these hashes correspond to the numbers 1371454 and 131. These two numbers need to be multiplied, as indicated by the “multiply them” hint from the following two md5 hashes.
Level 4. At this level there was a cant. Instead of capital letters, you must enter the password lowercase. Despite this cant, at least 4 people completed the level anyway. Words at this level are not at all in the subject, you need to count how many letters in each and do these operations with these numbers. We obtain the sequence of numbers 21, 14, 7, 19, 5, 9, which corresponds to the letters of the Latin alphabet s, n, g, u, e, i. Obviously, from these letters you can make the word "genius". This is confirmed by the fact that if the source words are arranged alphabetically, then the letters will stand in the correct order.
Level 5. With this level, some kind of trouble ... He was almost all brute-force (in the sense, they broke the password). In fact, from my point of view, it is the easiest. I warned you need to be able to use search on the Internet. Find the sequence A112676 in the encyclopedia of integer sequences. It says that this sequence gives the number of Hamiltonian cycles on a triangular lattice with n nodes on each side. For example, the following figure shows such a lattice for n = 4.
On it you can find 3 Hamilton cycles. It is seen that in the initial sequence there is no answer for n = 8. It is easy to calculate it on a regular home computer by writing an uncomplicated program that calculates Hamiltonian cycles for exhaustive search. Of course, if you write absolutely anyhow, the program will work for several hours. If you implement some simple clipping, then the work should not exceed 30 minutes. Many doubted that something had to be counted, but the clue was that the post was in the “Sport Programming” section. Don't you think it's just like that? Answer 1371454. By the way, this number has already met, is not it?
Although ... brute-force password was probably easier? This is not prohibited in the quest and fits the category of "the ability to use some tools."
Level 6. This level (along with the 9th) was most liked, judging by the feedback that came to me in the mail or in the LAN. It can be seen that the text on the assembler yasm, formatted somehow crookedly and unnaturally, suggests that the text is divided into 10 lines, and the hint says that the answer is 10 letters. Looking closely, you can see that each line contains spaces (code 32) and tabs (code 9) as separators between words. If we replace the spaces with the “.” Character, and the tabs with the “-” character, we get a Morse code. Armed with a table of correspondence of letters to sequences of "points" and "dashes", we get the word rationlity (intentionally written with an error). This is the password.
Level 7. The idea borrowed from Mary . Remembering the connection between levels 1 and 2, someone will think that once in the 6th level it is written about the assembler, then the Level7.asm file needs to be compiled. If someone understands the assembler and was able to run the program in DOS emulation mode, then he received the inscription "did you not think so?" It would be too easy! Use out of the box thinking. ”, In which perhaps only a malicious emoticon is missing. In fact, I am sure that many have found the solution without it, just looking at the comments. If you align comments with the “;” symbol, as is usually done in beautiful programs, you will get the numbers 3 5 9 0 2 6. You can break your head, what would that mean, or you can just enter 359026 as a password :)
Level 8. For some reason, too, brutforsili. There in the task file it is written that you need to draw a chessboard and build some kind of convex figure stretched on some points, then count the perimeter, area, multiply them, round down and convert to binary system (why is it so difficult? Inspiration ended, apparently ). In this case, in the task folder are 6 files, according to which it was necessary to guess which points on the chessboard to mark. So,
a.pdf - This is vitamin b5, which is easy to find on the Internet for the phrase that is in this document. So one of the points on the board would be b5.
b.pdf - “Almost 200” is 199. It is not difficult to guess what the 16th number system is, where there are letters (after all, coordinates on the chessboard are given by letters and numbers). 199 = 0xC7. So c7 is meant.
c.pdf - Completely stupid rebus. Mean E3. This puzzle appeared in my bewilderment. Initially, the idea was different - in the numerator to draw a picture from Wikipedia, which shows a method of encoding a fractional number with a single precision in the format of IEEE-754. But for some reason I thought and forgot about this idea. But I still would have solved it :)
d.png - This is a major seventh chord from the “mi” note. The figure depicts one of the options for his guitar. It is denoted in music through E7.
e.png - The F5 button on the keyboard is encrypted here, which in some cases is used to copy files.
f.jpg - This is the same Nokia-C3. The picture shows it.
Now draw a shape. It is intentionally made simple and symmetrical. In order to be able to guess one or two points, if the hints did not succumb (in fact, how many of the music lessons in school remember what a major seventh chord is and how are chords depicted on the guitar?).
The area of the figure is 12, and the perimeter is 4 + 4 * sqrt (5). Multiply, round down, we get 155. We need to write this number in binary as a password.
Level 9. The idea is also taken from Mary - I liked the idea to encode the message in the form of hidden pixels in the image. In front of you are 4 squares with flowers. Three of them hint at RGB, and the fourth hints that if they are combined, there will be a shade of gray (in this case, white). But before you connect the squares, you need to make the hidden pixels on each of them visible. This is done by almost any image editing tool that is able to select pixels of a given color. Combining the puzzle pieces, we get the password "nsvjkjltw", in which, with certain skills, you can guess the phrase "you are young." This level (along with the 6th) also liked a lot.
Next comes the final picture, in which I asked to inform me about the passage of the quest. Who made it at the moment was about 10 people. I am sure that many have passed and did not bother with notifications.
Now the answer to some "criticism" that took place. It is clear that there are always dissatisfied. Obviously, you can't please everyone. People are different and give everyone different tasks. However, I cannot accept the remark that in problems there are many ambiguities. Remember the game “What? Where? When?". There are such tasks when experts bring out some object or a black box in the hall. Sometimes (although not always) some phrase is said, and then a question like “call the phrase” is asked. Under the subject and the hint fits anything, absolutely any phrase, but experts still call the hidden phrase correctly (sometimes wrong, really). Why do they guess? Because they can see in the task something that clearly indicates the answer. Something with the help of which it becomes almost obvious that it was “this” that was made up, and not “that.” Let us examine the examples of dissatisfied.
I am told that in the first assignment I wanted to count the letters a, b, c, d, and count something using the above formula. With such reasoning, one can find out that other attempts are also suitable to combine letters in any way and other ways of counting, with any complexity. And I warned that there are NO serious ambiguities. So this logic is deliberately wrong, because it leads to too many options. And what's the point then to make letters in bold? Is it just so done? From here it was necessary to dance, and not to think that your pdf-viewer has glitches.
Someone said that in the second assignment, the asterisks and spaces can be interpreted as numbers in the binary system, and then add them or do anything with them. Does the task indicate something about it? Is it proposed to add somewhere (and why not multiply, divide or subtract?)? Not. So this logic is obviously wrong, since it leads to a mass of options, each of which in no way clearly follows from the task.
Well, and so on. I think that the tasks turned out to be generally successful, if you do not get hung up on an idea, but try to think more widely. Therefore, criticism of ambiguities is not accepted. If there were ambiguities, they were not so extensive that you could get lost in the options. Who passed the quest, did it calmly and did not seem to complain.
Thank you all for your interest! I myself was very interested to observe the development of events. Whose next turn to do puzzles?
Let me remind you that the default password is a number, and guess what kind of a number you can always, without getting into the deep jungle of ambiguities (as some participants thought). In addition, I warned in advance that participants should be a little familiar with programming.
')
Level 1. A pdf document is proposed with a narration about the determinant of a 2x2 matrix and about raising it to the fifth degree. There is no point here, but you can pay attention to the bold letters that make up the word mcmxlviii, which is very similar to writing a number in Roman notation. This number is 1948, it is a password.
Level 2. Of course, you can interpret the file of spaces and stars as you like. But how should a person who is looking for hidden information in a file reason? He will definitely check if there are any hidden characters that are not immediately visible. Take any normal hex-viewer and open the file in it, immediately seeing a 2x2 matrix consisting of numbers 4 7 1 8 in the simplified ASCII-art style. You might think that the answer is the number 4718 or some other 23 numbers that can be obtained from these numbers. But this is a wrong train of thought, since it leads to ambiguities, but it is believed that there are none. You do not think that I wrote the text about the determinant in the fifth degree on the previous level for nothing? The determinant is 25, and in the fifth degree it will be equal to 9765625.
Level 3. In this level hint. It should be clear that md5 hashes are written out. The first 6 of them have types that are easy to find on the Internet. They form the expression “use your brain and chromosomal crossover”. The following 2 hashes cannot be decrypted. Next, you need to look at what “chromosomal crossover” is and guess that the md5 hashes were split in half, and then the first half of the first hash is connected to the second half of the second and vice versa. Having done the reverse operation, you will find that these hashes correspond to the numbers 1371454 and 131. These two numbers need to be multiplied, as indicated by the “multiply them” hint from the following two md5 hashes.
Level 4. At this level there was a cant. Instead of capital letters, you must enter the password lowercase. Despite this cant, at least 4 people completed the level anyway. Words at this level are not at all in the subject, you need to count how many letters in each and do these operations with these numbers. We obtain the sequence of numbers 21, 14, 7, 19, 5, 9, which corresponds to the letters of the Latin alphabet s, n, g, u, e, i. Obviously, from these letters you can make the word "genius". This is confirmed by the fact that if the source words are arranged alphabetically, then the letters will stand in the correct order.
Level 5. With this level, some kind of trouble ... He was almost all brute-force (in the sense, they broke the password). In fact, from my point of view, it is the easiest. I warned you need to be able to use search on the Internet. Find the sequence A112676 in the encyclopedia of integer sequences. It says that this sequence gives the number of Hamiltonian cycles on a triangular lattice with n nodes on each side. For example, the following figure shows such a lattice for n = 4.
On it you can find 3 Hamilton cycles. It is seen that in the initial sequence there is no answer for n = 8. It is easy to calculate it on a regular home computer by writing an uncomplicated program that calculates Hamiltonian cycles for exhaustive search. Of course, if you write absolutely anyhow, the program will work for several hours. If you implement some simple clipping, then the work should not exceed 30 minutes. Many doubted that something had to be counted, but the clue was that the post was in the “Sport Programming” section. Don't you think it's just like that? Answer 1371454. By the way, this number has already met, is not it?
Although ... brute-force password was probably easier? This is not prohibited in the quest and fits the category of "the ability to use some tools."
Level 6. This level (along with the 9th) was most liked, judging by the feedback that came to me in the mail or in the LAN. It can be seen that the text on the assembler yasm, formatted somehow crookedly and unnaturally, suggests that the text is divided into 10 lines, and the hint says that the answer is 10 letters. Looking closely, you can see that each line contains spaces (code 32) and tabs (code 9) as separators between words. If we replace the spaces with the “.” Character, and the tabs with the “-” character, we get a Morse code. Armed with a table of correspondence of letters to sequences of "points" and "dashes", we get the word rationlity (intentionally written with an error). This is the password.
Level 7. The idea borrowed from Mary . Remembering the connection between levels 1 and 2, someone will think that once in the 6th level it is written about the assembler, then the Level7.asm file needs to be compiled. If someone understands the assembler and was able to run the program in DOS emulation mode, then he received the inscription "did you not think so?" It would be too easy! Use out of the box thinking. ”, In which perhaps only a malicious emoticon is missing. In fact, I am sure that many have found the solution without it, just looking at the comments. If you align comments with the “;” symbol, as is usually done in beautiful programs, you will get the numbers 3 5 9 0 2 6. You can break your head, what would that mean, or you can just enter 359026 as a password :)
Level 8. For some reason, too, brutforsili. There in the task file it is written that you need to draw a chessboard and build some kind of convex figure stretched on some points, then count the perimeter, area, multiply them, round down and convert to binary system (why is it so difficult? Inspiration ended, apparently ). In this case, in the task folder are 6 files, according to which it was necessary to guess which points on the chessboard to mark. So,
a.pdf - This is vitamin b5, which is easy to find on the Internet for the phrase that is in this document. So one of the points on the board would be b5.
b.pdf - “Almost 200” is 199. It is not difficult to guess what the 16th number system is, where there are letters (after all, coordinates on the chessboard are given by letters and numbers). 199 = 0xC7. So c7 is meant.
c.pdf - Completely stupid rebus. Mean E3. This puzzle appeared in my bewilderment. Initially, the idea was different - in the numerator to draw a picture from Wikipedia, which shows a method of encoding a fractional number with a single precision in the format of IEEE-754. But for some reason I thought and forgot about this idea. But I still would have solved it :)
d.png - This is a major seventh chord from the “mi” note. The figure depicts one of the options for his guitar. It is denoted in music through E7.
e.png - The F5 button on the keyboard is encrypted here, which in some cases is used to copy files.
f.jpg - This is the same Nokia-C3. The picture shows it.
Now draw a shape. It is intentionally made simple and symmetrical. In order to be able to guess one or two points, if the hints did not succumb (in fact, how many of the music lessons in school remember what a major seventh chord is and how are chords depicted on the guitar?).
The area of the figure is 12, and the perimeter is 4 + 4 * sqrt (5). Multiply, round down, we get 155. We need to write this number in binary as a password.
Level 9. The idea is also taken from Mary - I liked the idea to encode the message in the form of hidden pixels in the image. In front of you are 4 squares with flowers. Three of them hint at RGB, and the fourth hints that if they are combined, there will be a shade of gray (in this case, white). But before you connect the squares, you need to make the hidden pixels on each of them visible. This is done by almost any image editing tool that is able to select pixels of a given color. Combining the puzzle pieces, we get the password "nsvjkjltw", in which, with certain skills, you can guess the phrase "you are young." This level (along with the 6th) also liked a lot.
Next comes the final picture, in which I asked to inform me about the passage of the quest. Who made it at the moment was about 10 people. I am sure that many have passed and did not bother with notifications.
Now the answer to some "criticism" that took place. It is clear that there are always dissatisfied. Obviously, you can't please everyone. People are different and give everyone different tasks. However, I cannot accept the remark that in problems there are many ambiguities. Remember the game “What? Where? When?". There are such tasks when experts bring out some object or a black box in the hall. Sometimes (although not always) some phrase is said, and then a question like “call the phrase” is asked. Under the subject and the hint fits anything, absolutely any phrase, but experts still call the hidden phrase correctly (sometimes wrong, really). Why do they guess? Because they can see in the task something that clearly indicates the answer. Something with the help of which it becomes almost obvious that it was “this” that was made up, and not “that.” Let us examine the examples of dissatisfied.
I am told that in the first assignment I wanted to count the letters a, b, c, d, and count something using the above formula. With such reasoning, one can find out that other attempts are also suitable to combine letters in any way and other ways of counting, with any complexity. And I warned that there are NO serious ambiguities. So this logic is deliberately wrong, because it leads to too many options. And what's the point then to make letters in bold? Is it just so done? From here it was necessary to dance, and not to think that your pdf-viewer has glitches.
Someone said that in the second assignment, the asterisks and spaces can be interpreted as numbers in the binary system, and then add them or do anything with them. Does the task indicate something about it? Is it proposed to add somewhere (and why not multiply, divide or subtract?)? Not. So this logic is obviously wrong, since it leads to a mass of options, each of which in no way clearly follows from the task.
Well, and so on. I think that the tasks turned out to be generally successful, if you do not get hung up on an idea, but try to think more widely. Therefore, criticism of ambiguities is not accepted. If there were ambiguities, they were not so extensive that you could get lost in the options. Who passed the quest, did it calmly and did not seem to complain.
Thank you all for your interest! I myself was very interested to observe the development of events. Whose next turn to do puzzles?
Source: https://habr.com/ru/post/135782/
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