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Crypto 1

This entry was posted on Apr 22 2012

 

Crypto1 – 100 Points

Cipher text:

87 101 108 99 111 109 101 32 116 111 32 116 104 101 32 50 48 49 49 32 78 89 85 32 80 111 108 121 32 67 83 65 87 32 67 84 70 32 101 118 101 110 116 46 32 87 101 32 104 97 118 101 32 112 108 97 110 110 101 100 32 109 97 110 121 32 99 104 97 108 108 101 110 103 101 115 32 102 111 114 32 121 111 117 32 97 110 100 32 119 101 32 104 111 112 101 32 121 111 117 32 104 97 118 101 32 102 117 110 32 115 111 108 118 105 110 103 32 116 104 101 109 32 97 108 108 46 32 84 104 101 32 107 101 121 32 102 111 114 32 116 104 105 115 32 99 104 97 108 108 101 110 103 101 32 105 115 32 99 114 121 112 116 111 103 114 97 112 104 121 46

Solving:

The numbers are ASCII codes, replace them with their actual characters.

awk: available on Linux, or cygwin (a mingw port probably exists too).

awk looks at each field.

awk sees each “word” separated with a space as a field:

  • $0 = whole line
  • $1 = first field
  • $2 = second field
  • NF = number of fields on one line

The for loop, loops trough all fields from $1 to the last field on the line: for (i=1; i <= nf=”" i=”" strong=”">

Inside the loop ‘printf(“%c”, $i);‘ converts the ASCII value of the current field (controlled by the loop) to its character value.

$ printf '87 101 108 99 111 109 101 32 116 111 32 116 104 101 32 50 48 49 49 32 78 89 85 32 80 111 108 121 32 67 83 65 87 32 67 84 70 32 101 118 101 110 116 46 32 87 101 32 104 97 118 101 32 112 108 97 110 110 101 100 32 109 97 110 121 32 99 104 97 108 108 101 110 103 101 115 32 102 111 114 32 121 111 117 32 97 110 100 32 119 101 32 104 111 112 101 32 121 111 117 32 104 97 118 101 32 102 117 110 32 115 111 108 118 105 110 103 32 116 104 101 109 32 97 108 108 46 32 84 104 101 32 107 101 121 32 102 111 114 32 116 104 105 115 32 99 104 97 108 108 101 110 103 101 32 105 115 32 99 114 121 112 116 111 103 114 97 112 104 121 46' | awk '{ for (i=1; i <= NF; i++) { printf("%c", $i); } }'

Solution:

Welcome to the 2011 NYU Poly CSAW CTF event. We have planned many challenges for you and we hope you have fun solving them all. The key for this challenge is cryptography.

Or you can do it the easy way with xlate Translator's [ASCII DEC / CHAR]  section.

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