34 lines
1.3 KiB
Python
34 lines
1.3 KiB
Python
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#!/usr/bin/env python3
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"""Generate a one-time pad of uppercase letters from /dev/urandom."""
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import sys
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def generate_daybook(weeks: int = 52):
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for week in range(1, weeks + 1):
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with open(f"daybook_week_{week:02d}.txt", "w") as f:
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f.write(f"WEEK {week:02d}\n\n")
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f.write(format_pad(generate_pad(500)))
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def generate_pad(num_letters: int) -> str:
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"""Read raw bytes from /dev/urandom and map them uniformly to A-Z."""
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letters = []
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with open("/dev/urandom", "rb") as f:
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while len(letters) < num_letters:
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b = f.read(1)[0]
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# Reject bytes >= 234 to avoid modulo bias.
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# 234 = 9 * 26, so bytes 0..233 map uniformly to 0..25.
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if b < 234:
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letters.append(chr((b % 26) + 65))
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return "".join(letters)
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def format_pad(text: str, group_size: int = 5, groups_per_line: int = 10) -> str:
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"""Format as 5-letter groups, 10 groups per line — classic OTP layout."""
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groups = [text[i:i + group_size] for i in range(0, len(text), group_size)]
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lines = [" ".join(groups[i:i + groups_per_line])
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for i in range(0, len(groups), groups_per_line)]
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return "\n".join(lines)
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if __name__ == "__main__":
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n = int(sys.argv[1]) if len(sys.argv) > 1 else 500
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print(format_pad(generate_pad(n)))
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