cmd/bnscli: use mnemonic to generate private key

Instead of generating a random private key use algorithm described in
https://github.com/iov-one/iov-core/blob/master/docs/address-derivation-v1.md
to create a mnemonic and later use that mnemonic to create a private
key.

resolve #855

Tests are missing.

cmd/bnscli/cmd_key.go

@@ -1,21 +1,25 @@
 package main
 
 import (
+	"bytes"
 	"flag"
 	"fmt"
 	"io"
 	"io/ioutil"
 	"os"
 
 	"github.com/iov-one/weave/crypto"
+	"github.com/iov-one/weave/crypto/bech32"
+	"github.com/stellar/go/exp/crypto/derivation"
+	"github.com/tyler-smith/go-bip39"
 	"golang.org/x/crypto/ed25519"
 )
 
 func cmdKeygen(input io.Reader, output io.Writer, args []string) error {
 	fl := flag.NewFlagSet("", flag.ExitOnError)
 	fl.Usage = func() {
 		fmt.Fprint(flag.CommandLine.Output(), `
-Generate a new private key.
+Read mnemonic and generate a new private key.
 
 When successful a new file with binary content containing private key is
 created. This command fails if the private key file already exists.
@@ -25,6 +29,7 @@ created. This command fails if the private key file already exists.
 	var (
 		keyPathFl = fl.String("key", env("BNSCLI_PRIV_KEY", os.Getenv("HOME")+"/.bnsd.priv.key"),
 			"Path to the private key file that transaction should be signed with. You can use BNSCLI_PRIV_KEY environment variable to set it.")
+		pathFl = fl.String("path", "m/44'/234'/0'", "Derivation path as described in BIP-44.")
 	)
 	fl.Parse(args)
 
@@ -35,9 +40,17 @@ created. This command fails if the private key file already exists.
 		return fmt.Errorf("private key file %q already exists, delete this file and try again", *keyPathFl)
 	}
 
-	_, priv, err := ed25519.GenerateKey(nil)
+	mnemonic, err := readInput(input)
 	if err != nil {
-		return fmt.Errorf("cannot generate ed25519 key: %s", err)
+		return fmt.Errorf("cannot read mnemonic: %s", err)
+	}
+
+	// We do not allow for passphrase.
+	seed := bip39.NewSeed(string(mnemonic), "")
+
+	key, err := derivation.DeriveForPath(*pathFl, seed)
+	if err != nil {
+		return fmt.Errorf("cannot deriviate master key from seed: %s", err)
 	}
 
 	fd, err := os.OpenFile(*keyPathFl, os.O_CREATE|os.O_WRONLY, 0400)
@@ -46,6 +59,11 @@ created. This command fails if the private key file already exists.
 	}
 	defer fd.Close()
 
+	_, priv, err := ed25519.GenerateKey(bytes.NewReader(key.Key))
+	if err != nil {
+		return fmt.Errorf("cannot generate ed25519 private key: %s", err)
+	}
+
 	if _, err := fd.Write(priv); err != nil {
 		return fmt.Errorf("cannot write private key: %s", err)
 	}
@@ -83,6 +101,38 @@ Print out a hex-address associated with your private key.
 			Ed25519: raw,
 		},
 	}
-	_, err = fmt.Fprintln(output, key.PublicKey().Address())
+
+	bech, err := bech32.Encode("iov", key.PublicKey().GetEd25519())
+	if err != nil {
+		return fmt.Errorf("cannot generate bech32 address format: %s", err)
+	}
+
+	fmt.Fprintf(output, "bech32\t%s\n", bech)
+	fmt.Fprintf(output, "hex\t%s\n", key.PublicKey().Address())
+	return nil
+}
+
+func cmdMnemonic(input io.Reader, output io.Writer, args []string) error {
+	fl := flag.NewFlagSet("", flag.ExitOnError)
+	fl.Usage = func() {
+		fmt.Fprint(flag.CommandLine.Output(), `
+Generate and print out a mnemonic.
+`)
+	}
+	var (
+		bitSizeFl = fl.Uint("size", 256, "Bit size of the entropy. Must be between 128 and 256.")
+	)
+	fl.Parse(args)
+
+	entropy, err := bip39.NewEntropy(int(*bitSizeFl))
+	if err != nil {
+		return fmt.Errorf("cannot create entropy instance: %s", err)
+	}
+	mnemonic, err := bip39.NewMnemonic(entropy)
+	if err != nil {
+		return fmt.Errorf("cannot create mnemonic instance: %s", err)
+	}
+
+	_, err = fmt.Fprintln(output, mnemonic)
 	return err
 }

cmd/bnscli/common.go

@@ -7,6 +7,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
@@ -182,3 +183,22 @@ func tendermintStore(nodeURL string) weave.ReadOnlyKVStore {
 	tm := rpcclient.NewHTTP(nodeURL, "/websocket")
 	return app.NewABCIStore(rpcQueryWrapper{tm})
 }
+
+// readInput returns all bytes waiting on given input. This function immediatly
+// returns errNoPipe error if the input is not piped to avoid forever waiting.
+func readInput(input io.Reader) ([]byte, error) {
+	// If the given reader is providing a stat information (ie os.Stdin)
+	// then check if the data is being piped. That should prevent us from
+	// waiting for a data on a reader that no one ever writes to.
+	if s, ok := input.(stater); ok {
+		if info, err := s.Stat(); err == nil {
+			isPipe := (info.Mode() & os.ModeCharDevice) == 0
+			if !isPipe {
+				return nil, errNoPipe
+			}
+		}
+	}
+	return ioutil.ReadAll(input)
+}
+
+var errNoPipe = errors.New("no data piped")

cmd/bnscli/main.go

@@ -42,6 +42,7 @@ var commands = map[string]func(input io.Reader, output io.Writer, args []string)
 	"from-sequence":             cmdFromSequence,
 	"keyaddr":                   cmdKeyaddr,
 	"keygen":                    cmdKeygen,
+	"mnemonic":                  cmdMnemonic,
 	"multisig":                  cmdMultisig,
 	"query":                     cmdQuery,
 	"register-username":         cmdRegisterUsername,

go.mod

@@ -17,12 +17,13 @@ require (
 	github.com/prometheus/client_golang v0.9.3 // indirect
 	github.com/rcrowley/go-metrics v0.0.0-20181016184325-3113b8401b8a // indirect
 	github.com/rs/cors v1.6.0 // indirect
-	github.com/stellar/go v0.0.0-20190524153138-e5e03dc34e2d
+	github.com/stellar/go v0.0.0-20190723221356-14eed5a46caf
 	github.com/stellar/go-xdr v0.0.0-20180917104419-0bc96f33a18e // indirect
 	github.com/syndtr/goleveldb v1.0.0 // indirect
 	github.com/tendermint/go-amino v0.15.0
 	github.com/tendermint/iavl v0.12.2
 	github.com/tendermint/tendermint v0.31.5
+	github.com/tyler-smith/go-bip39 v1.0.0
 	golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f
 	google.golang.org/grpc v1.21.0 // indirect
 )

go.sum

@@ -108,8 +108,8 @@ github.com/rs/cors v1.6.0 h1:G9tHG9lebljV9mfp9SNPDL36nCDxmo3zTlAf1YgvzmI=
 github.com/rs/cors v1.6.0/go.mod h1:gFx+x8UowdsKA9AchylcLynDq+nNFfI8FkUZdN/jGCU=
 github.com/sirupsen/logrus v1.2.0/go.mod h1:LxeOpSwHxABJmUn/MG1IvRgCAasNZTLOkJPxbbu5VWo=
 github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=
-github.com/stellar/go v0.0.0-20190524153138-e5e03dc34e2d h1:qlw1pPjIH7Uo9t1BeP+/pHvqAxB0Yq22zLpWzY1Uu4I=
-github.com/stellar/go v0.0.0-20190524153138-e5e03dc34e2d/go.mod h1:Kkro8X6IWn/5XtSicGd6N2LZKMKUCWS5wS5Ctjh6+Vw=
+github.com/stellar/go v0.0.0-20190723221356-14eed5a46caf h1:gLIFkwCtIquj9iFCPy595EFSmgJbQIZMLAG6gFHcNrI=
+github.com/stellar/go v0.0.0-20190723221356-14eed5a46caf/go.mod h1:Kkro8X6IWn/5XtSicGd6N2LZKMKUCWS5wS5Ctjh6+Vw=
 github.com/stellar/go-xdr v0.0.0-20180917104419-0bc96f33a18e h1:n/hfey8pO+RYMoGXyvyzuw5pdO8IFDoyAL/g5OiCesY=
 github.com/stellar/go-xdr v0.0.0-20180917104419-0bc96f33a18e/go.mod h1:gpOLVzy6TVYTQ3LvHSN9RJC700FkhFCpSE82u37aNRM=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
@@ -125,6 +125,8 @@ github.com/tendermint/iavl v0.12.2 h1:Ls5p5VINCM1HRT9g5Vvs2zmDOCU/CCIvIHzd/pZ8P0
 github.com/tendermint/iavl v0.12.2/go.mod h1:EoKMMv++tDOL5qKKVnoIqtVPshRrEPeJ0WsgDOLAauM=
 github.com/tendermint/tendermint v0.31.5 h1:vTet8tCq3B9/J9Yo11dNZ8pOB7NtSy++bVSfkP4KzR4=
 github.com/tendermint/tendermint v0.31.5/go.mod h1:ymcPyWblXCplCPQjbOYbrF1fWnpslATMVqiGgWbZrlc=
+github.com/tyler-smith/go-bip39 v1.0.0 h1:FOHg9gaQLeBBRbHE/QrTLfEiBHy5pQ/yXzf9JG5pYFM=
+github.com/tyler-smith/go-bip39 v1.0.0/go.mod h1:sJ5fKU0s6JVwZjjcUEX2zFOnvq0ASQ2K9Zr6cf67kNs=
 golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20180904163835-0709b304e793/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=