2 files changed, 79 insertions, 18 deletions

diff --git a/tools/genpem.go b/tools/genpem.go
index 542fd9a..182c630 100644
--- a/tools/genpem.go
+++ b/tools/genpem.go
@@ -1,42 +1,45 @@
 package main
 
 import (
+	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
+	"errors"
 	"math/big"
 	"os"
+	"slices"
 )
 
-const (
-	P = "1201758001370723323398753778257470257713354828752713123415294815" +
-		"0506251412291888866940292054989907714155267326586216043845592229" +
-		"084368540020196135619327879"
-
-	Q = "1189892136861686835188050824611210139447876026576932541274639840" +
-		"5473436969889506919017477758618276066588858607419440134394668095" +
-		"105156501566867770737187273"
-
-	E = "65537"
-)
-
-func main() {
+func GenerateDefaultKey() (*rsa.PrivateKey, error) {
 	// NOTE(fusion): Generate key from known P, Q, and E. There isn't a helper
 	// function from the standard library so we need to build the private key
 	// ourselves.
+	const (
+		P = "1201758001370723323398753778257470257713354828752713123415294815" +
+			"0506251412291888866940292054989907714155267326586216043845592229" +
+			"084368540020196135619327879"
+
+		Q = "1189892136861686835188050824611210139447876026576932541274639840" +
+			"5473436969889506919017477758618276066588858607419440134394668095" +
+			"105156501566867770737187273"
+
+		E = "65537"
+	)
+
 	p, ok := new(big.Int).SetString(P, 10)
 	if !ok || !p.ProbablyPrime(4) {
-		panic("invalid P")
+		return nil, errors.New("invalid default P prime")
 	}
 
 	q, ok := new(big.Int).SetString(Q, 10)
 	if !ok || !q.ProbablyPrime(4) {
-		panic("invalid Q")
+		return nil, errors.New("invalid default Q prime")
 	}
 
 	e, ok := new(big.Int).SetString(E, 10)
 	if !ok || !e.IsInt64() || !e.ProbablyPrime(4) {
-		panic("invalid E")
+		return nil, errors.New("invalid default E prime")
 	}
 
 	pMinus1 := new(big.Int).Sub(p, big.NewInt(1))
@@ -56,16 +59,40 @@ func main() {
 		Primes: []*big.Int{p, q},
 	}
 
+	return &privateKey, nil
+}
+
+func GenerateKey() (*rsa.PrivateKey, error) {
+	return rsa.GenerateKey(rand.Reader, 1024)
+}
+
+func main() {
+	var (
+		privateKey *rsa.PrivateKey
+		err        error
+	)
+
+	if len(os.Args) > 1 && slices.Contains(os.Args[1:], "-default") {
+		privateKey, err = GenerateDefaultKey()
+	} else {
+		privateKey, err = GenerateKey()
+	}
+
+	if err != nil {
+		panic("failed to generate key: " + err.Error())
+	}
+
 	// NOTE(fusion): `Validate()` will only perform minor sanity checks. To actually
 	// check that the output key is valid use `openssl rsa -in KEY.PEM -check`.
-	if err := privateKey.Validate(); err != nil {
+	err = privateKey.Validate()
+	if err != nil {
 		panic("invalid private key: " + err.Error())
 	}
 
 	// NOTE(fusion): Dump private key into stdout.
 	block := pem.Block{
 		Type:  "RSA PRIVATE KEY",
-		Bytes: x509.MarshalPKCS1PrivateKey(&privateKey),
+		Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
 	}
 	pem.Encode(os.Stdout, &block)
 }
diff --git a/tools/pubkey.go b/tools/pubkey.go
new file mode 100644
index 0000000..4649664
--- /dev/null
+++ b/tools/pubkey.go
@@ -0,0 +1,34 @@
+package main
+
+import (
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"log"
+	"os"
+)
+
+func main() {
+	keyFile := "key.pem"
+	if len(os.Args) > 1 {
+		keyFile = os.Args[1]
+	}
+
+	keyData, err := os.ReadFile(keyFile)
+	if err != nil {
+		log.Panicf("failed to read key \"%v\": %v", keyFile, err)
+	}
+
+	keyBlock, _ := pem.Decode(keyData)
+	if keyBlock == nil {
+		log.Panicf("key \"%v\" is empty")
+	}
+
+	privateKey, err := x509.ParsePKCS1PrivateKey(keyBlock.Bytes)
+	if err != nil {
+		log.Panic("failed to read PKCS1 RSA private key: %v", err)
+	}
+
+	fmt.Println("N", privateKey.N)
+	fmt.Println("E", privateKey.E)
+}