create some test vectors

cli/main.go

@@ -0,0 +1,143 @@
+package main
+
+import (
+  "os"
+  "fmt"
+  "encoding/hex"
+	"github.com/boltcard/boltcard/crypto"
+)
+
+// inspired by parse_request() in lnurlw_request.go
+
+func check_cmac(uid []byte, ctr []byte, k2_cmac_key []byte, cmac []byte) (bool, error) {
+
+	sv2 := make([]byte, 16)
+	sv2[0] = 0x3c
+	sv2[1] = 0xc3
+	sv2[2] = 0x00
+	sv2[3] = 0x01
+	sv2[4] = 0x00
+	sv2[5] = 0x80
+	sv2[6] = uid[0]
+	sv2[7] = uid[1]
+	sv2[8] = uid[2]
+	sv2[9] = uid[3]
+	sv2[10] = uid[4]
+	sv2[11] = uid[5]
+	sv2[12] = uid[6]
+	sv2[13] = ctr[0]
+	sv2[14] = ctr[1]
+	sv2[15] = ctr[2]
+
+	cmac_verified, err := crypto.Aes_cmac(k2_cmac_key, sv2, cmac)
+
+	if err != nil {
+		return false, err
+	}
+
+	return cmac_verified, nil
+}
+
+func main() {
+
+  fmt.Println("-- bolt card crypto test vectors --")
+  fmt.Println()
+
+  args := os.Args[1:]
+
+  if(len(args) != 4) {
+    fmt.Println("error: should have arguments for: p c aes_decrypt_key aes_cmac_key")
+    os.Exit(1)
+  }
+
+// get from args
+  p_hex := args[0]
+  c_hex := args[1]
+  aes_decrypt_key_hex := args[2]
+  aes_cmac_key_hex := args[3]
+
+  fmt.Println("p = ", p_hex)
+  fmt.Println("c = ", c_hex)
+  fmt.Println("aes_decrypt_key = ", aes_decrypt_key_hex)
+  fmt.Println("aes_cmac_key = ", aes_cmac_key_hex)
+  fmt.Println()
+
+  p, err := hex.DecodeString(p_hex)
+
+	if err != nil {
+    fmt.Println("ERROR: p not valid hex", err)
+    os.Exit(1)
+	}
+
+	c, err := hex.DecodeString(c_hex)
+
+	if err != nil {
+    fmt.Println("ERROR: c not valid hex", err)
+    os.Exit(1)
+	}
+
+	if len(p) != 16 {
+    fmt.Println("ERROR: p length not valid")
+    os.Exit(1)
+	}
+
+	if len(c) != 8 {
+    fmt.Println("ERROR: c length not valid")
+    os.Exit(1)
+	}
+
+	// decrypt p with aes_decrypt_key
+
+	aes_decrypt_key, err := hex.DecodeString(aes_decrypt_key_hex)
+
+	if err != nil {
+    fmt.Println("ERROR: DecodeString() returned an error", err)
+    os.Exit(1)
+	}
+
+	dec_p, err := crypto.Aes_decrypt(aes_decrypt_key, p)
+
+	if err != nil {
+    fmt.Println("ERROR: Aes_decrypt() returned an error", err)
+    os.Exit(1)
+	}
+
+	if dec_p[0] != 0xC7 {
+    fmt.Println("ERROR: decrypted data does not start with 0xC7 so is invalid")
+    os.Exit(1)
+	}
+
+	uid := dec_p[1:8]
+	ctr := dec_p[8:11]
+
+	// set up uid & ctr for card record if needed
+
+	uid_str := hex.EncodeToString(uid)
+	ctr_str := hex.EncodeToString(ctr)
+
+  fmt.Println("decrypted card data : uid", uid_str, ", ctr", ctr_str)
+
+	// check cmac
+
+	aes_cmac_key, err := hex.DecodeString(aes_cmac_key_hex)
+
+	if err != nil {
+    fmt.Println("ERROR: aes_cmac_key is not valid hex", err)
+    os.Exit(1)
+	}
+
+	cmac_valid, err := check_cmac(uid, ctr, aes_cmac_key, c)
+
+	if err != nil {
+    fmt.Println("ERROR: check_cmac() returned an error", err)
+    os.Exit(1)
+	}
+
+	if cmac_valid == false {
+    fmt.Println("ERROR: cmac incorrect")
+    os.Exit(1)
+	}
+
+  fmt.Println("cmac validates ok")
+  os.Exit(0)
+}