Generating RSA keys based on p, q, and exponent

Generating RSA keys based on p, q, and exponent

Post by Jeronimo B » Sun, 10 Feb 2008 04:46:31


Hello,

Is there any function to generate public/private keys based on known p, q
and exponent values and use these in RSACryptoServiceProvider?

Thanks.
 
 
 

Generating RSA keys based on p, q, and exponent

Post by Valery Pry » Tue, 12 Feb 2008 17:20:20

On Feb 8, 8:46m, Jeronimo Bertran


for RSA you know private key when you have modulus (p*q) and
decryption exponent. since you have p and q and exponent d - means
that you already have private key.

if you have both exponents and modulus (but no p and q) - its easy to
find p and q.
if you have (p-1)*(q-1) and one of exponents - to find second exponent
just take multiplicative inverse of first exponent mod (p-1)*(q-1).

if you ask about CRT (Chinese Remainder Theorem) optimization for RSA
decryption when you have d, p and q, all you need is just to calculate
multiplicative inverses of P and Q...

all above could be done easily with help of any biginteger library
that supports modular operations...

-Valery