Add example to compute opc

examples/compute_opc/main.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"encoding/hex"
+	"flag"
+	"fmt"
+	"log"
+
+	"github.com/wmnsk/milenage"
+)
+
+func main() {
+	var (
+		ks  = flag.String("k", "00112233445566778899aabbccddeeff", "K in hex string")
+		ops = flag.String("op", "00112233445566778899aabbccddeeff", "OP in hex string")
+	)
+	flag.Parse()
+
+	k, err := hex.DecodeString(*ks)
+	if err != nil {
+		log.Fatalf("Invalid K \"%s\": %+v", *ks, err)
+	}
+	op, err := hex.DecodeString(*ops)
+	if err != nil {
+		log.Fatalf("Invalid OP \"%s\": %+v", *ops, err)
+	}
+
+	opc, err := milenage.ComputeOPc(k, op)
+	if err != nil {
+		log.Fatalf("Failed to compute: %+v", err)
+	}
+
+	fmt.Printf("%x\n", opc)
+}