1 files changed, 63 insertions, 0 deletions
diff --git a/main.go b/main.go
new file mode 100644
index 0000000..6297ad9
--- /dev/null
+++ b/main.go
@@ -0,0 +1,63 @@
+// SPDX-FileCopyrightText: © 2021 Grégoire Duchêne <gduchene@awhk.org>
+// SPDX-License-Identifier: ISC
+
+package main
+
+import (
+	"bytes"
+	"encoding/base64"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"os"
+
+	"github.com/hashicorp/vault/shamir"
+)
+
+var (
+	combine = flag.Bool("c", false, "combine instead of split")
+	parts   = flag.Int("p", 10, "parts to split the secret into")
+	thres   = flag.Int("t", 2, "threshold required to reconstruct the secret")
+)
+
+func main() {
+	flag.Parse()
+
+	buf, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "failed to read the secret:", err)
+		os.Exit(1)
+	}
+
+	if !*combine {
+		parts, err := shamir.Split(buf, *parts, *thres)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "failed to split the secret:", err)
+			os.Exit(1)
+		}
+		for _, part := range parts {
+			fmt.Println(base64.StdEncoding.EncodeToString(part))
+		}
+		return
+	}
+
+	parts := [][]byte{}
+	for _, buf := range bytes.Split(buf, []byte("\n")) {
+		if len(buf) == 0 {
+			continue
+		}
+		part := make([]byte, base64.StdEncoding.DecodedLen(len(buf)))
+		n, err := base64.StdEncoding.Decode(part, buf)
+		if err != nil {
+			fmt.Fprintln(os.Stderr, "failed to decode a part:", err)
+			os.Exit(1)
+		}
+		parts = append(parts, part[:n])
+	}
+	sec, err := shamir.Combine(parts)
+	if err != nil {
+		fmt.Fprintln(os.Stderr, "failed to combine parts:", err)
+		os.Exit(1)
+	}
+	fmt.Print(string(sec))
+}