// This example demonstrates how to generate a cryptographically random seed
// then use it to create a new master node (extended key).
func ExampleNewMaster() {
// Generate a random seed at the recommended length.
seed, err := hdkeychain.GenerateSeed(hdkeychain.RecommendedSeedLen)
if err != nil {
fmt.Println(err)
return
}
// Generate a new master node using the seed.
key, err := hdkeychain.NewMaster(seed)
if err != nil {
fmt.Println(err)
return
}
// Show that the generated master node extended key is private.
fmt.Println("Private Extended Key?:", key.IsPrivate())
// Output:
// Private Extended Key?: true
}
// TestGenenerateSeed ensures the GenerateSeed function works as intended.
func TestGenenerateSeed(t *testing.T) {
wantErr := errors.New("seed length must be between 128 and 512 bits")
tests := []struct {
name string
length uint8
err error
}{
// Test various valid lengths.
{name: "16 bytes", length: 16},
{name: "17 bytes", length: 17},
{name: "20 bytes", length: 20},
{name: "32 bytes", length: 32},
{name: "64 bytes", length: 64},
// Test invalid lengths.
{name: "15 bytes", length: 15, err: wantErr},
{name: "65 bytes", length: 65, err: wantErr},
}
for i, test := range tests {
seed, err := hdkeychain.GenerateSeed(test.length)
if !reflect.DeepEqual(err, test.err) {
t.Errorf("GenerateSeed #%d (%s): unexpected error -- "+
"want %v, got %v", i, test.name, test.err, err)
continue
}
if test.err == nil && len(seed) != int(test.length) {
t.Errorf("GenerateSeed #%d (%s): length mismatch -- "+
"got %d, want %d", i, test.name, len(seed),
test.length)
continue
}
}
}
// TestErrors performs some negative tests for various invalid cases to ensure
// the errors are handled properly.
func TestErrors(t *testing.T) {
// Should get an error when seed has too few bytes.
_, err := hdkeychain.NewMaster(bytes.Repeat([]byte{0x00}, 15))
if err != hdkeychain.ErrInvalidSeedLen {
t.Errorf("NewMaster: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrInvalidSeedLen)
}
// Should get an error when seed has too many bytes.
_, err = hdkeychain.NewMaster(bytes.Repeat([]byte{0x00}, 65))
if err != hdkeychain.ErrInvalidSeedLen {
t.Errorf("NewMaster: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrInvalidSeedLen)
}
// Generate a new key and neuter it to a public extended key.
seed, err := hdkeychain.GenerateSeed(hdkeychain.RecommendedSeedLen)
if err != nil {
t.Errorf("GenerateSeed: unexpected error: %v", err)
return
}
extKey, err := hdkeychain.NewMaster(seed)
if err != nil {
t.Errorf("NewMaster: unexpected error: %v", err)
return
}
pubKey, err := extKey.Neuter()
if err != nil {
t.Errorf("Neuter: unexpected error: %v", err)
return
}
// Deriving a hardened child extended key should fail from a public key.
_, err = pubKey.Child(hdkeychain.HardenedKeyStart)
if err != hdkeychain.ErrDeriveHardFromPublic {
t.Errorf("Child: mismatched error -- got: %v, want: %v",
err, hdkeychain.ErrDeriveHardFromPublic)
}
// NewKeyFromString failure tests.
tests := []struct {
name string
key string
err error
neuter bool
neuterErr error
}{
{
name: "invalid key length",
key: "xpub1234",
err: hdkeychain.ErrInvalidKeyLen,
},
{
name: "bad checksum",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ29ESFjqJoCu1Rupje8YtGqsefD265TMg7usUDFdp6W1EBygr15",
err: hdkeychain.ErrBadChecksum,
},
{
name: "pubkey not on curve",
key: "xpub661MyMwAqRbcFtXgS5sYJABqqG9YLmC4Q1Rdap9gSE8NqtwybGhePY2gZ1hr9Rwbk95YadvBkQXxzHBSngB8ndpW6QH7zhhsXZ2jHyZqPjk",
err: errors.New("pubkey isn't on secp256k1 curve"),
},
{
name: "unsupported version",
key: "xbad4LfUL9eKmA66w2GJdVMqhvDmYGJpTGjWRAtjHqoUY17sGaymoMV9Cm3ocn9Ud6Hh2vLFVC7KSKCRVVrqc6dsEdsTjRV1WUmkK85YEUujAPX",
err: nil,
neuter: true,
neuterErr: chaincfg.ErrUnknownHDKeyID,
},
}
for i, test := range tests {
extKey, err := hdkeychain.NewKeyFromString(test.key)
if !reflect.DeepEqual(err, test.err) {
t.Errorf("NewKeyFromString #%d (%s): mismatched error "+
"-- got: %v, want: %v", i, test.name, err,
test.err)
continue
}
if test.neuter {
_, err := extKey.Neuter()
if !reflect.DeepEqual(err, test.neuterErr) {
t.Errorf("Neuter #%d (%s): mismatched error "+
"-- got: %v, want: %v", i, test.name,
err, test.neuterErr)
continue
}
}
}
}