new BigInteger(String) performance / complexity

Question

I\'m wondering about the performance/complexity of constructing BigInteger objects with the new BigInteger(String) constructor

Answer 1

The O(n^2) effort is caused by the decimal to binary conversion if the BigInteger is specified as decimal digits.

Also, 10^7 digits is a really huge number. For typical cryptographic algorithms like RSA you would deal with 10^3 to 10^4 digits. Most of the BigInteger operations are not optimized for such a large number of digits.