diff --git a/lib/tools/phono_byte.dart b/lib/tools/phono_byte.dart
index 0531f94..683372f 100644
--- a/lib/tools/phono_byte.dart
+++ b/lib/tools/phono_byte.dart
@@ -1,8 +1,9 @@
 // Implementation of https://github.com/meeb/phonobyte
-
+import 'dart:convert';
 import 'dart:typed_data';
+import 'package:charcode/charcode.dart';
 
-const phonoWords = [
+const _byteToPhono = [
   'jab',
   'tip',
   'led',
@@ -261,23 +262,81 @@ const phonoWords = [
   'tab'
 ];
 
-String prettyPhonoString(String s) {
+Map<String, int> _phonoToByte = _buildPhonoToByte();
 
+Map<String, int> _buildPhonoToByte() {
+  Map<String, int> phonoToByte = {};
+  for (int b = 0; b < 256; b++) {
+    String ph = _byteToPhono[b];
+    phonoToByte[ph] = b;
+  }
+  return phonoToByte;
+}
+
+String prettyPhonoString(String s,
+    {int wordsPerLine = 5, int phonoPerWord = 2}) {
+  assert(wordsPerLine >= 1);
+  assert(phonoPerWord >= 1);
+  final cs = canonicalPhonoString(s).toUpperCase();
+  String out = "";
+  int words = 0;
+  int phonos = 0;
+  for (int i = 0; i < cs.length; i += 3) {
+    if (i != 0) {
+      phonos += 1;
+      if (phonos == phonoPerWord) {
+        phonos = 0;
+        words += 1;
+        if (words == wordsPerLine) {
+          words = 0;
+          out += "\n";
+        } else {
+          out += " ";
+        }
+      }
+    }
+    out += cs.substring(i, i + 3);
+  }
+  return out;
 }
 
 String canonicalPhonoString(String s) {
-
+  Uint8List bytes = Uint8List.fromList(utf8.encode(s.toLowerCase()));
+  String cs = "";
+  for (int i = 0; i < bytes.length; i++) {
+    int ch = bytes[i];
+    if (ch >= $a && ch <= $z) {
+      cs += String.fromCharCode(ch);
+    }
+  }
+  if (cs.length % 3 != 0) {
+    throw const FormatException(
+        "phonobyte string length should be a multiple of 3");
+  }
+  for (int i = 0; i < cs.length; i += 3) {
+    String ph = cs.substring(i, i + 3);
+    if (!_phonoToByte.containsKey(ph)) {
+      throw const FormatException("phonobyte string contains invalid sequence");
+    }
+  }
+  return cs;
 }
 
 Uint8List decodePhono(String s) {
-    
-  try {
-
+  final cs = canonicalPhonoString(s);
+  final out = Uint8List(cs.length ~/ 3);
+  for (int i = 0; i < cs.length; i += 3) {
+    String ph = cs.substring(i, i + 3);
+    int b = _phonoToByte[ph]!;
+    out[i] = b;
   }
-//FormatException
-
+  return out;
 }
 
 String encodePhono(Uint8List b) {
-
+  String out = "";
+  for (int i = 0; i < b.length; i++) {
+    out += _byteToPhono[b[i]];
+  }
+  return out;
 }
diff --git a/pubspec.lock b/pubspec.lock
index bdd1ec2..5c83de5 100644
--- a/pubspec.lock
+++ b/pubspec.lock
@@ -146,7 +146,7 @@ packages:
     source: hosted
     version: "1.3.0"
   charcode:
-    dependency: transitive
+    dependency: "direct main"
     description:
       name: charcode
       sha256: fb98c0f6d12c920a02ee2d998da788bca066ca5f148492b7085ee23372b12306
diff --git a/pubspec.yaml b/pubspec.yaml
index 20a6d9d..4ebb7d6 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -38,6 +38,7 @@ dependencies:
   intl: ^0.18.0
   fixnum: ^1.1.0
   protobuf: ^3.0.0
+  charcode: ^1.3.1
 
 dev_dependencies:
   flutter_test: