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gf_informatik:verschluesselung:codierung [2026-03-31 06:27] – hofgf_informatik:verschluesselung:codierung [2026-04-09 06:40] (aktuell) – hof
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 In Python können wir einen Buchstaben mit der `ord()` Funktion in die entsprechende ASCII-Zahl verwandeln. `ord` steht für _ordinal value_, also die Ordnungszahl eines Buchstabens in der ASCII-Textcodierung. In Python können wir einen Buchstaben mit der `ord()` Funktion in die entsprechende ASCII-Zahl verwandeln. `ord` steht für _ordinal value_, also die Ordnungszahl eines Buchstabens in der ASCII-Textcodierung.
-<HTML><script type="module" src="https://bottom.ch/ksr/ed/bottom-editor.js"></script></HTML>+<HTML><script type="module" src="https://bottom.ch/editor/stable/bottom-editor.js"></script></HTML>
    
 <HTML><bottom-editor>letter = 'A'  # Muss ein einzelner Buchstabe sein! <HTML><bottom-editor>letter = 'A'  # Muss ein einzelner Buchstabe sein!
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 ``` ```
  
-<nodisp 2>+<nodisp 1>
 ++++Lösung:| ++++Lösung:|
 <code python decrypt.py> <code python decrypt.py>
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 ++++ ++++
 </nodisp> </nodisp>
- 
 ### Aufgabe 5 (optional) ### Aufgabe 5 (optional)
  
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 <nodisp 1> <nodisp 1>
 ++++ Lösung| ++++ Lösung|
-<code python>+<html><bottom-editor layout="split"> 
 +# In normal python: pip install opencv-python numpy 
 +import micropip 
 +await micropip.install(["numpy", "opencv-python"]); 
 import cv2 as cv import cv2 as cv
 import numpy as np import numpy as np
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 key = "11110000011001101100010000110101110010111001100100010110000111110001100101000101101110111111000000000011000000111110010111101010111110001110101010101000001111001010110110100111000000000011111111010001111100110111101001111010000001011101010000101111110101001100010101001011011101110101011001110100100001101110110011000110100100111100010011001100100111000000000011011110000100010010001110101100111101010100111100010001010100101100111101101011100110110000000000101000000010100111110010000011101000111001100000101011110000000100110011000001000101001000011101000100100100100010100111110011101011010101010110001011010001001010000111000100100010111001111100011100001000011001100011100110101101111001000110001001111010111111100001111111111111011101100101111100000101000101100101011111111110001010111000101010110011011010111111101111110100000100100101001000100101100111100010101011111111001001101000011001101111000111111110101100001100110110000101100000000010111110001011011010010010000111010010011001101010010100000011101111110100101001111110011010000101001111001111000000010101111001000101100110010111101111001000010110111101000110110101000101110001001011100111110010111001011111111010000010011000011101100110111001001000110001110110011011000011001010001111000101100100001010110011000001011100001011010011010001110101010001111000000111111101110011000010010000111010111000111000110" key = "11110000011001101100010000110101110010111001100100010110000111110001100101000101101110111111000000000011000000111110010111101010111110001110101010101000001111001010110110100111000000000011111111010001111100110111101001111010000001011101010000101111110101001100010101001011011101110101011001110100100001101110110011000110100100111100010011001100100111000000000011011110000100010010001110101100111101010100111100010001010100101100111101101011100110110000000000101000000010100111110010000011101000111001100000101011110000000100110011000001000101001000011101000100100100100010100111110011101011010101010110001011010001001010000111000100100010111001111100011100001000011001100011100110101101111001000110001001111010111111100001111111111111011101100101111100000101000101100101011111111110001010111000101010110011011010111111101111110100000100100101001000100101100111100010101011111111001001101000011001101111000111111110101100001100110110000101100000000010111110001011011010010010000111010010011001101010010100000011101111110100101001111110011010000101001111001111000000010101111001000101100110010111101111001000010110111101000110110101000101110001001011100111110010111001011111111010000010011000011101100110111001001000110001110110011011000011001010001111000101100100001010110011000001011100001011010011010001110101010001111000000111111101110011000010010000111010111000111000110"
  
-img = cv.imread('encryption/bild_raetsel_xor_1373.png')+img_url = 'https://sca.ksr.ch/lib/exe/fetch.php?cache=&media=gf_informatik:umgang_inet_sca:bild_raetsel_xor_1373.png' 
 +# In vanilla python, use urllib.request.urlopen(img_url) 
 +from pyodide.http import pyfetch 
 +response = await pyfetch(img_url) 
 +data = await response.bytes() 
 + 
 +arr = np.asarray(bytearray(data), dtype=np.uint8) 
 +img = cv.imdecode(arr, -1) # 'Load it as it is' 
 # Note that the key length (in bits) is not byte-aligned (not a multiple of 8). # Note that the key length (in bits) is not byte-aligned (not a multiple of 8).
 print(img.size) print(img.size)
 print(len(key)) print(len(key))
- +  
-# Repeat the key as often as necessary to match the image length.+# Repeat the key as often as necessary to match the image length.
 key = key * math.ceil(img.size*8 / len(key)) key = key * math.ceil(img.size*8 / len(key))
 key_offset = 0 key_offset = 0
 + 
 # Process each pixel # Process each pixel
 for x in range(img.shape[0]): for x in range(img.shape[0]):
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         img[x,y] = b, g, r         img[x,y] = b, g, r
         key_offset = key_offset + 24         key_offset = key_offset + 24
 + 
 cv.imshow('image',img) cv.imshow('image',img)
 cv.waitKey() cv.waitKey()
-</code>+</bottom-editor></html>
 ++++ ++++
 </nodisp> </nodisp>
  
  • gf_informatik/verschluesselung/codierung.1774938479.txt.gz
  • Zuletzt geändert: 2026-03-31 06:27
  • von hof