Just reading Ron Rivest's explanation of MD4 the hash uses two round constants one $ \text{5A827999}$ on round $2$ and the other $\text{6ED9EBA1}$ on round $3$.

I think they are supposed to be hex representation of square root of $2$ and $3$. But $\sqrt{2} = 1.\text{6A09E667F} $ and

$\sqrt{3} = 1.\text{BB67AE858}$

which are very different from the the values given. Any ideas?

  • $\begingroup$ ok this one might have a better view and explanation. $\endgroup$
    – Aven Desta
    Commented Mar 1, 2019 at 6:58
  • $\begingroup$ If you can find a straight answer in there then self-answering the question is highly appreciated. $\endgroup$
    – Maarten Bodewes
    Commented Mar 1, 2019 at 14:39
  • 1
    $\begingroup$ Ok, but I did not find the answer, the numbers don't add up. And I really appreciate anyone with any suggestion. $\endgroup$
    – Aven Desta
    Commented Mar 1, 2019 at 18:48
  • $\begingroup$ Still stuck but new development. The book "Donald E. Knuth. Seminumerical Algorithms, volume 2, page 660" is mentioned here just after the constants. So I tried to find the book but no luck. $\endgroup$
    – Aven Desta
    Commented Mar 1, 2019 at 20:49

1 Answer 1


I've got the solution myself in here

It says

SHA-1 was designed by NSA and uses the constants 5a827999, 6ed9eba1, 8f1bbcdc, and ca62c1d6. In case you haven't already noticed, these are hex representations of $2^{30}$ times the square roots of 2, 3, 5 and 10.


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