lib: update `RSAGenKey`

Add `size` argument.

1 files changed, 4 insertions, 3 deletions

diff --git a/lib/rsa.go b/lib/rsa.go
index 772b898..9353824 100644
--- a/lib/rsa.go
+++ b/lib/rsa.go
@@ -68,7 +68,8 @@ func InvMod(a, n *big.Int) (*big.Int, error) {
 	return t0, nil
 }
 
-func RSAGenKey() (*RSAPair, error) {
+// RSAGenKey generates a rsa key pair with N equal to size bits.
+func RSAGenKey(size int) (*RSAPair, error) {
 	// Initialize.
 	e := big.NewInt(3)
 	d := big.NewInt(0)
@@ -77,13 +78,13 @@ func RSAGenKey() (*RSAPair, error) {
 	// Compute n and d.
 	for {
 		// Generate prime p.
-		p, err := rand.Prime(rand.Reader, 1024)
+		p, err := rand.Prime(rand.Reader, size/2)
 		if err != nil {
 			return nil, CPError{"unable to generate p"}
 		}
 
 		// Generate prime q.
-		q, err := rand.Prime(rand.Reader, 1024)
+		q, err := rand.Prime(rand.Reader, size/2)
 		if err != nil {
 			return nil, CPError{"unable to generate q"}
 		}