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The alternation of substitution from the S-boxes , and permutation of bits from the P-box and E-expansion provides so-called " confusion and diffusion " respectively , a concept identified by Claude Shannon in the 1940 s as a necessary condition for a secure yet practical cipher .
 Claude Shannon
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Claude Shannon