The puzzle in the second volume of The Art of Computer Programming has been solved! The composite cofactor of the public key was the product of 91-digit and 97-digit prime numbers:
91-digit prime factor:
97-digit prime factor:
With these and the previously known 25-digit prime factor, 1144729885849400174143427, we are able to decrypt the RSA-encrypted literary quote. The quote is the following:
His remarks (as reported) were as follows:--
"O Rowty-owty tiddly-owty
--G. K. Chesterton (1905)
This is from The Tremendous Adventures of Major Brown, the first in the collection of short stories The Club of Queer Trades.