From 32803d4577151e18252c7e2102738b544e99fcbc Mon Sep 17 00:00:00 2001
From: siddharth ravikumar <s@ricketyspace.net>
Date: Mon, 14 Oct 2024 19:16:11 -0400
Subject: lib: update `RSAGenKey`

Add `size` argument.
---
 Makefile         | 2 +-
 challenge/c39.go | 2 +-
 challenge/c40.go | 2 +-
 challenge/c41.go | 2 +-
 cryptopals.go    | 2 ++
 lib/rsa.go       | 7 ++++---
 lib/rsa_test.go  | 4 ++--
 7 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/Makefile b/Makefile
index 1605733..f95095c 100644
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,7 @@ vet:
 .PHONY: vet
 
 test:
-	go test ${ARGS} ${MOD}/lib
+	go test ${ARGS} ${MOD}/lib ${RUN_ARGS}
 .PHONY: test
 
 clean:
diff --git a/challenge/c39.go b/challenge/c39.go
index 6261c13..fbdb6f9 100644
--- a/challenge/c39.go
+++ b/challenge/c39.go
@@ -10,7 +10,7 @@ import (
 )
 
 func C39() {
-	rsa, err := lib.RSAGenKey()
+	rsa, err := lib.RSAGenKey(2048)
 	if err != nil {
 		fmt.Printf("gen key failed: %v", err)
 		return
diff --git a/challenge/c40.go b/challenge/c40.go
index ec16059..c12b74c 100644
--- a/challenge/c40.go
+++ b/challenge/c40.go
@@ -16,7 +16,7 @@ func C40() {
 	// Generate 3 rsa key pairs and capture the their public keys.
 	var rsaPubs []*lib.RSAPub
 	for i := 0; i < 3; i++ {
-		rsa, err := lib.RSAGenKey()
+		rsa, err := lib.RSAGenKey(2048)
 		if err != nil {
 			fmt.Printf("gen key failed: %v", err)
 			return
diff --git a/challenge/c41.go b/challenge/c41.go
index 4ef983d..532f62b 100644
--- a/challenge/c41.go
+++ b/challenge/c41.go
@@ -12,7 +12,7 @@ import (
 
 func C41() {
 	// Generate RSA key pair and setup paraphernalia.
-	kpair, err := lib.RSAGenKey()
+	kpair, err := lib.RSAGenKey(2048)
 	if err != nil {
 		fmt.Printf("rsa gen key: %v\n", err)
 		return
diff --git a/cryptopals.go b/cryptopals.go
index 5d02e56..a22c9fc 100644
--- a/cryptopals.go
+++ b/cryptopals.go
@@ -102,5 +102,7 @@ func main() {
 		challenge.C40()
 	case 41:
 		challenge.C41()
+	case 42:
+		challenge.C42()
 	}
 }
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"}
 		}
diff --git a/lib/rsa_test.go b/lib/rsa_test.go
index d26ee2c..810d7cc 100644
--- a/lib/rsa_test.go
+++ b/lib/rsa_test.go
@@ -59,7 +59,7 @@ func TestInvMod(t *testing.T) {
 }
 
 func TestRSAGenKey(t *testing.T) {
-	pair, err := RSAGenKey()
+	pair, err := RSAGenKey(2048)
 	if err != nil {
 		t.Errorf("genkey: %v", err)
 		return
@@ -95,7 +95,7 @@ func TestRSAGenKey(t *testing.T) {
 }
 
 func TestRSAEncryptDecrypt(t *testing.T) {
-	pair, err := RSAGenKey()
+	pair, err := RSAGenKey(2048)
 	if err != nil {
 		t.Errorf("genkey: %v", err)
 		return
-- 
cgit v1.2.3