fix(chisel): convert seed to private key file EE-5099 (#9149)

api/chisel/crypto/crypto.go

@@ -0,0 +1,61 @@
+package crypto
+
+import (
+	"crypto/ecdsa"
+	"crypto/elliptic"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"io"
+	"math/big"
+
+	chshare "github.com/jpillora/chisel/share"
+)
+
+var one = new(big.Int).SetInt64(1)
+
+// GenerateGo119CompatibleKey This function is basically copied from chshare.GenerateKey.
+func GenerateGo119CompatibleKey(seed string) ([]byte, error) {
+	r := chshare.NewDetermRand([]byte(seed))
+	priv, err := ecdsaGenerateKey(elliptic.P256(), r)
+	if err != nil {
+		return nil, err
+	}
+	b, err := x509.MarshalECPrivateKey(priv)
+	if err != nil {
+		return nil, fmt.Errorf("Unable to marshal ECDSA private key: %w", err)
+	}
+	return pem.EncodeToMemory(&pem.Block{Type: "EC PRIVATE KEY", Bytes: b}), nil
+}
+
+// This function is copied from Go1.19
+func randFieldElement(c elliptic.Curve, rand io.Reader) (k *big.Int, err error) {
+	params := c.Params()
+	// Note that for P-521 this will actually be 63 bits more than the order, as
+	// division rounds down, but the extra bit is inconsequential.
+	b := make([]byte, params.N.BitLen()/8+8)
+	_, err = io.ReadFull(rand, b)
+	if err != nil {
+		return
+	}
+
+	k = new(big.Int).SetBytes(b)
+	n := new(big.Int).Sub(params.N, one)
+	k.Mod(k, n)
+	k.Add(k, one)
+	return
+}
+
+// This function is copied from Go1.19
+func ecdsaGenerateKey(c elliptic.Curve, rand io.Reader) (*ecdsa.PrivateKey, error) {
+	k, err := randFieldElement(c, rand)
+	if err != nil {
+		return nil, err
+	}
+
+	priv := new(ecdsa.PrivateKey)
+	priv.PublicKey.Curve = c
+	priv.D = k
+	priv.PublicKey.X, priv.PublicKey.Y = c.ScalarBaseMult(k.Bytes())
+	return priv, nil
+}

api/chisel/crypto/crypto_test.go

@@ -0,0 +1,37 @@
+package crypto
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestGenerateGo119CompatibleKey(t *testing.T) {
+	type args struct {
+		seed string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    []byte
+		wantErr bool
+	}{
+		{
+			name:    "Generate Go 1.19 compatible private key with a given seed",
+			args:    args{seed: "94qh17MCIk8BOkiI"},
+			want:    []byte("-----BEGIN EC PRIVATE KEY-----\nMHcCAQEEIHeohwk0Gy3RHVVViaHz7pz/HOiqA7fkv1FTM3mGgfT3oAoGCCqGSM49\nAwEHoUQDQgAEN7riX06xDsLNPuUmOvYFluNEakcFwZZRVvOcIYk/9VYnanDzW0Km\n8/BUUiKyJDuuGdS4fj9SlQ4iL8yBK01uKg==\n-----END EC PRIVATE KEY-----\n"),
+			wantErr: false,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := GenerateGo119CompatibleKey(tt.args.seed)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("GenerateGo119CompatibleKey() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("GenerateGo119CompatibleKey()\ngot: Z %v\nwant: %v", got, tt.want)
+			}
+		})
+	}
+}