Swap base58 libraries (#472)

* Swap base58 libraries

This doesn't reduce binary size but it removes a metric ton of
dependencies.

internal/cmd/base/base.go

@@ -3,6 +3,7 @@ package base
 import (
 	"bytes"
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"flag"
 	"fmt"
@@ -15,7 +16,6 @@ import (
 	"sync"
 	"syscall"
 
-	"github.com/btcsuite/btcutil/base58"
 	"github.com/hashicorp/boundary/api"
 	"github.com/hashicorp/boundary/api/authtokens"
 	"github.com/hashicorp/boundary/sdk/wrapper"
@@ -219,10 +219,13 @@ func (c *Command) Client(opt ...Option) (*api.Client, error) {
 				token = ""
 			}
 			if token != "" {
-				tokenBytes := base58.Decode(token)
-				if len(tokenBytes) == 0 {
+				tokenBytes, err := base64.RawStdEncoding.DecodeString(token)
+				switch {
+				case err != nil:
+					c.UI.Error(fmt.Errorf("Error base64-unmarshaling stored token from system credential store: %w", err).Error())
+				case len(tokenBytes) == 0:
 					c.UI.Error("Zero length token after decoding stored token from system credential store")
-				} else {
+				default:
 					var authToken authtokens.AuthToken
 					if err := json.Unmarshal(tokenBytes, &authToken); err != nil {
 						c.UI.Error(fmt.Sprintf("Error unmarshaling stored token information after reading from system credential store: %s", err))

internal/cmd/commands/authenticate/password.go

@@ -1,13 +1,13 @@
 package authenticate
 
 import (
+	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"os"
 	"strings"
 	"time"
 
-	"github.com/btcsuite/btcutil/base58"
 	"github.com/hashicorp/boundary/api"
 	"github.com/hashicorp/boundary/api/authmethods"
 	"github.com/hashicorp/boundary/internal/cmd/base"
@@ -165,7 +165,7 @@ func (c *PasswordCommand) Run(args []string) int {
 			c.UI.Error(fmt.Sprintf("Error marshaling auth token to save to system credential store: %s", err))
 			return 1
 		}
-		if err := keyring.Set("HashiCorp Boundary Auth Token", tokenName, base58.Encode(marshaled)); err != nil {
+		if err := keyring.Set("HashiCorp Boundary Auth Token", tokenName, base64.RawStdEncoding.EncodeToString(marshaled)); err != nil {
 			c.UI.Error(fmt.Sprintf("Error saving auth token to system credential store: %s", err))
 			return 1
 		}

internal/cmd/commands/proxy/proxy.go

@@ -20,7 +20,6 @@ import (
 	"syscall"
 	"time"
 
-	"github.com/btcsuite/btcutil/base58"
 	"github.com/hashicorp/boundary/api"
 	"github.com/hashicorp/boundary/api/targets"
 	"github.com/hashicorp/boundary/globals"
@@ -30,6 +29,7 @@ import (
 	"github.com/hashicorp/go-cleanhttp"
 	"github.com/hashicorp/vault/sdk/helper/base62"
 	"github.com/mitchellh/cli"
+	"github.com/mr-tron/base58"
 	"github.com/posener/complete"
 	"go.uber.org/atomic"
 	"google.golang.org/protobuf/proto"
@@ -391,7 +391,11 @@ func (c *Command) Run(args []string) (retCode int) {
 		authzString = sa.AuthorizationToken
 	}
 
-	marshaled := base58.Decode(authzString)
+	marshaled, err := base58.FastBase58Decoding(authzString)
+	if err != nil {
+		c.UI.Error(fmt.Errorf("Unable to base58-decode authorization data: %w", err).Error())
+		return 1
+	}
 	if len(marshaled) == 0 {
 		c.UI.Error("Zero length authorization information after decoding")
 		return 1