gbucchino
33 lines
1008 B
Python
33 lines
1008 B
Python
#!/usr/bin/env python3
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from math import erfc, sqrt
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def monobit_test(bitseq: str):
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"""
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Frequency (Monobit) Test for a binary sequence. This tests count the number of '1' and '0' in a bit sequence and make a test statistics
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This test is based on the NIST SP 800-22 document, that describe how to perform tests for PRNG algorithms:
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https://nvlpubs.nist.gov/nistpubs/legacy/sp/nistspecialpublication800-22r1a.pdf
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Returns:
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p_value (float): larger p-values suggest consistency with randomness.
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"""
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n = len(bitseq)
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if n == 0:
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raise ValueError("bitseq must not be empty")
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if any(c not in "01" for c in bitseq):
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raise ValueError("bitseq must contain only '0' and '1'")
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# Count ones and zeros via +/-1 sum
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s = sum(1 if c == "1" else -1 for c in bitseq)
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# Compute the test statistic
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sobs = abs(s) / sqrt(n)
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# Compute p-value, based on the Complementary Error Function (erfc)
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p_value = erfc(sobs / sqrt(2))
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return p_value
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