Change all the arguments to use base16 from base64.

WARNING: THIS BREAKS BACKWARD COMPATIBILITY.

This is primarily to work around bug #12930.  Base16 was chosen over
unpadded Base64 because the go runtime Base64 decoder does not handle
omitting the padding.

May $deity have mercy on anyone who needs to hand-enter an obfs4 bridge
line because I will not.

2 files changed, 11 insertions, 16 deletions

diff --git a/transports/obfs4/obfs4.go b/transports/obfs4/obfs4.go
index fbfea27..f9b02ad 100644
--- a/transports/obfs4/obfs4.go
+++ b/transports/obfs4/obfs4.go
@@ -117,8 +117,8 @@ func (t *Transport) ServerFactory(stateDir string, args *pt.Args) (base.ServerFa
 
 	// Store the arguments that should appear in our descriptor for the clients.
 	ptArgs := pt.Args{}
-	ptArgs.Add(nodeIDArg, st.nodeID.Base64())
-	ptArgs.Add(publicKeyArg, st.identityKey.Public().Base64())
+	ptArgs.Add(nodeIDArg, st.nodeID.Hex())
+	ptArgs.Add(publicKeyArg, st.identityKey.Public().Hex())
 
 	// Initialize the replay filter.
 	filter, err := replayfilter.New(replayTTL)
@@ -154,7 +154,7 @@ func (cf *obfs4ClientFactory) ParseArgs(args *pt.Args) (interface{}, error) {
 		return nil, fmt.Errorf("missing argument '%s'", nodeIDArg)
 	}
 	var nodeID *ntor.NodeID
-	if nodeID, err = ntor.NodeIDFromBase64(nodeIDStr); err != nil {
+	if nodeID, err = ntor.NodeIDFromHex(nodeIDStr); err != nil {
 		return nil, err
 	}
 
@@ -163,7 +163,7 @@ func (cf *obfs4ClientFactory) ParseArgs(args *pt.Args) (interface{}, error) {
 		return nil, fmt.Errorf("missing argument '%s'", publicKeyArg)
 	}
 	var publicKey *ntor.PublicKey
-	if publicKey, err = ntor.PublicKeyFromBase64(publicKeyStr); err != nil {
+	if publicKey, err = ntor.PublicKeyFromHex(publicKeyStr); err != nil {
 		return nil, err
 	}
 
diff --git a/transports/obfs4/statefile.go b/transports/obfs4/statefile.go
index e727f7d..378eefa 100644
--- a/transports/obfs4/statefile.go
+++ b/transports/obfs4/statefile.go
@@ -28,7 +28,6 @@
 package obfs4
 
 import (
-	"encoding/base64"
 	"encoding/json"
 	"fmt"
 	"io/ioutil"
@@ -85,17 +84,13 @@ func serverStateFromJSONServerState(js *jsonServerState) (*obfs4ServerState, err
 	var err error
 
 	st := new(obfs4ServerState)
-	if st.nodeID, err = ntor.NodeIDFromBase64(js.NodeID); err != nil {
+	if st.nodeID, err = ntor.NodeIDFromHex(js.NodeID); err != nil {
 		return nil, err
 	}
-	if st.identityKey, err = ntor.KeypairFromBase64(js.PrivateKey); err != nil {
+	if st.identityKey, err = ntor.KeypairFromHex(js.PrivateKey); err != nil {
 		return nil, err
 	}
-	var rawSeed []byte
-	if rawSeed, err = base64.StdEncoding.DecodeString(js.DrbgSeed); err != nil {
-		return nil, err
-	}
-	if st.drbgSeed, err = drbg.SeedFromBytes(rawSeed); err != nil {
+	if st.drbgSeed, err = drbg.SeedFromHex(js.DrbgSeed); err != nil {
 		return nil, err
 	}
 
@@ -138,10 +133,10 @@ func newJSONServerState(stateDir string, js *jsonServerState) (err error) {
 	}
 
 	// Encode it into JSON format and write the state file.
-	js.NodeID = st.nodeID.Base64()
-	js.PrivateKey = st.identityKey.Private().Base64()
-	js.PublicKey = st.identityKey.Public().Base64()
-	js.DrbgSeed = st.drbgSeed.Base64()
+	js.NodeID = st.nodeID.Hex()
+	js.PrivateKey = st.identityKey.Private().Hex()
+	js.PublicKey = st.identityKey.Public().Hex()
+	js.DrbgSeed = st.drbgSeed.Hex()
 
 	var encoded []byte
 	if encoded, err = json.Marshal(js); err != nil {