Created
September 29, 2018 17:45
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[Detect cipher block size] #blockcipher #crypto #oracle #detection
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| def detect_block_size(cipher_box): | |
| last_size = len(cipher_box('A')) | |
| counter = 0 | |
| while True: | |
| counter += 1 | |
| new_size = len(cipher_box('A' * counter)) | |
| if new_size > last_size: | |
| return new_size - last_size | |
| last_size = new_size | |
| # cipher_box is a function that accepts plain-text and returns cipher-text |
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