Attack and defense world crypto WP

One 、 Catalog

1.base64

2.caesar

3.Morse

4. Idempotent encryption

5.Railfence

6. Mixed encoding

Two 、 Their thinking

1.base64

  Open the file attachment

  The prompt given in the title is base64 encryption , Decrypt online

  obtain flag:   cyberpeace{Welcome_to_new_World!}

2.caesar

Open the file attachment

  The title says yes caesar encryption , Decrypt online ,key The value of the 0~25 One by one, try to be on duty 14 When you get rid of flag

 3.Morse

Open the file attachment

  The title has told us that it is moss encryption , Then observe that the attachments are made of 1 and 0 form , Just like the one in moss code - and . Take care of each other

Edit the file as -- --- .-. ... . -.-. In the form of

  Then decrypt

 flag：cyberpeace{morsecodeissointeresting}

4. Idempotent encryption

Open the file attachment

  The encryption method mentioned in the title is idempotent encryption , But we observe the attachment , Normal idempotent encryption only starts from 0~5, There will be no 8,

I learned through Baidu that this is the cloud shadow password , Let's first learn about cloud shadow encryption .

Cloud shadow encryption ： Cloud shadow encryption , also called 01248 password … Unlike binary power encryption , This encryption method uses 0 Make interval , Other than 0 Numbers are separated and combined to represent serial numbers 1~26 One of the letters （a/A,b/B,c/C…z/Z).

View Title Requirements flag For the eight capital letters solved , According to the nature of cloud shadow encryption , With 0 Separate this string of arrays as an interval, which is exactly eight groups , Add the numbers in each array , Then the total number corresponds to A~Z Letters in .

 

flag:cyberpeace{WELLDONE}

5.Railfence

  According to the title, it is fence encryption , There are two kinds of fence encryption , There is another way W Type fence encryption , Decrypt the attachment first , The title says 5 A chicken , therefore key May be 5

 

  And the result seems to be incorrect flag, Then the characters are W Type fence decryption

 flag：cyberpeace{railfence_cipher_gogogo}

6. Mixed encoding

Open the file attachment

There are two equal signs at the end of the file , It can be seen that base64 encryption , To decrypt

  Baidu knows that the character revealed is an encryption method , by Unicode code , Turn it into ascll code

  Observation characters have English case and numbers , May be base64 encryption , To decrypt

  Observe the decrypted characters , Between numbers / Separated and these numbers do not exceed 126, It may correspond to ascll clock , Put these numbers one A contrast ascll clock

flag：cyberpeace{welcometoattackanddefenceworld}