# How were the constants chosen in round 2 and 3 in MD4?

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?

• ok this one might have a better view and explanation. Mar 1, 2019 at 6:58
• If you can find a straight answer in there then self-answering the question is highly appreciated. Mar 1, 2019 at 14:39
• Ok, but I did not find the answer, the numbers don't add up. And I really appreciate anyone with any suggestion. Mar 1, 2019 at 18:48
• 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. Mar 1, 2019 at 20:49

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.