crypto: Add crypto.DEFAULT_ENCODING (defaults to 'buffer')

This is a flag to make it easier for users to upgrade through the
breaking crypto change, and easier for us to switch it back if it's a
problem.

Explicitly set default encoding to 'buffer' in other tests, in case it
ever changes back.

Author: isaacs

doc/api/crypto.markdown

@@ -19,6 +19,10 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+// Note: In 0.8 and before, crypto functions all defaulted to using
+// binary-encoded strings rather than buffers.
+
+exports.DEFAULT_ENCODING = 'buffer';
 
 try {
   var binding = process.binding('crypto');
@@ -137,15 +141,17 @@ function Hash(algorithm) {
 }
 
 Hash.prototype.update = function(data, encoding) {
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding === 'buffer')
     encoding = null;
-  if (encoding || typeof data === 'string')
+  if (typeof data === 'string')
     data = new Buffer(data, encoding);
   this._binding.update(data);
   return this;
 };
 
 Hash.prototype.digest = function(outputEncoding) {
+  outputEncoding = outputEncoding || exports.DEFAULT_ENCODING;
   var result = this._binding.digest('buffer');
   if (outputEncoding && outputEncoding !== 'buffer')
     result = result.toString(outputEncoding);
@@ -191,6 +197,8 @@ function Cipher(cipher, password) {
 }
 
 Cipher.prototype.update = function(data, inputEncoding, outputEncoding) {
+  inputEncoding = inputEncoding || exports.DEFAULT_ENCODING;
+  outputEncoding = outputEncoding || exports.DEFAULT_ENCODING;
   if (inputEncoding && inputEncoding !== 'buffer')
     data = new Buffer(data, inputEncoding);
 
@@ -205,6 +213,7 @@ Cipher.prototype.update = function(data, inputEncoding, outputEncoding) {
 };
 
 Cipher.prototype.final = function(outputEncoding) {
+  outputEncoding = outputEncoding || exports.DEFAULT_ENCODING;
   var ret = this._binding.final('buffer');
 
   if (outputEncoding && outputEncoding !== 'buffer') {
@@ -296,6 +305,7 @@ Sign.prototype.sign = function(key, encoding) {
   if (typeof key === 'string')
     key = new Buffer(key, 'binary');
 
+  encoding = encoding || exports.DEFAULT_ENCODING;
   var ret = this._binding.sign(key, 'buffer');
   if (encoding && encoding !== 'buffer')
     ret = ret.toString(encoding);
@@ -319,6 +329,7 @@ Verify.prototype.verify = function(object, signature, sigEncoding) {
   if (typeof object === 'string')
     object = new Buffer(object, 'binary');
 
+  sigEncoding = sigEncoding || exports.DEFAULT_ENCODING;
   if (sigEncoding === 'buffer')
     sigEncoding = null;
   if (sigEncoding || typeof signature === 'string')
@@ -336,22 +347,26 @@ function DiffieHellman(sizeOrKey, encoding) {
   if (!sizeOrKey)
     this._binding = new binding.DiffieHellman();
   else {
+    encoding = encoding || exports.DEFAULT_ENCODING;
     if (encoding === 'buffer')
       encoding = null;
-    if (encoding || typeof sizeOrKey === 'string')
+    if (typeof sizeOrKey === 'string')
       sizeOrKey = new Buffer(sizeOrKey, encoding);
     this._binding = new binding.DiffieHellman(sizeOrKey, 'buffer');
   }
 }
 
 DiffieHellman.prototype.generateKeys = function(encoding) {
   var keys = this._binding.generateKeys('buffer');
-  if (encoding)
+  encoding = encoding || exports.DEFAULT_ENCODING;
+  if (encoding && encoding !== 'buffer')
     keys = keys.toString(encoding);
   return keys;
 };
 
 DiffieHellman.prototype.computeSecret = function(key, inEnc, outEnc) {
+  inEnc = inEnc || exports.DEFAULT_ENCODING;
+  outEnc = outEnc || exports.DEFAULT_ENCODING;
   if (inEnc === 'buffer')
     inEnc = null;
   if (outEnc === 'buffer')
@@ -366,33 +381,38 @@ DiffieHellman.prototype.computeSecret = function(key, inEnc, outEnc) {
 
 DiffieHellman.prototype.getPrime = function(encoding) {
   var prime = this._binding.getPrime('buffer');
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding && encoding !== 'buffer')
     prime = prime.toString(encoding);
   return prime;
 };
 
 DiffieHellman.prototype.getGenerator = function(encoding) {
   var generator = this._binding.getGenerator('buffer');
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding && encoding !== 'buffer')
     generator = generator.toString(encoding);
   return generator;
 };
 
 DiffieHellman.prototype.getPublicKey = function(encoding) {
   var key = this._binding.getPublicKey('buffer');
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding && encoding !== 'buffer')
     key = key.toString(encoding);
   return key;
 };
 
 DiffieHellman.prototype.getPrivateKey = function(encoding) {
   var key = this._binding.getPrivateKey('buffer');
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding && encoding !== 'buffer')
     key = key.toString(encoding);
   return key;
 };
 
 DiffieHellman.prototype.setPublicKey = function(key, encoding) {
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding === 'buffer')
     encoding = null;
   if (encoding || typeof key === 'string')
@@ -402,6 +422,7 @@ DiffieHellman.prototype.setPublicKey = function(key, encoding) {
 };
 
 DiffieHellman.prototype.setPrivateKey = function(key, encoding) {
+  encoding = encoding || exports.DEFAULT_ENCODING;
   if (encoding === 'buffer')
     encoding = null;
   if (encoding || typeof key === 'string')
@@ -445,7 +466,22 @@ exports.pbkdf2 = function(password, salt, iterations, keylen, callback) {
     password = new Buffer(password, 'binary');
   if (typeof salt === 'string')
     salt = new Buffer(salt, 'binary');
-  return binding.PBKDF2(password, salt, iterations, keylen, callback);
+
+  if (exports.DEFAULT_ENCODING === 'buffer')
+    return binding.PBKDF2(password, salt, iterations, keylen, callback);
+
+  // at this point, we need to handle encodings.
+  var encoding = exports.DEFAULT_ENCODING;
+  if (callback) {
+    binding.PBKDF2(password, salt, iterations, keylen, function(er, ret) {
+      if (ret)
+        ret = ret.toString(encoding);
+      callback(er, ret);
+    });
+  } else {
+    var ret = binding.PBKDF2(password, salt, iterations, keylen);
+    return ret.toString(encoding);
+  }
 };
 
 exports.pbkdf2Sync = function(password, salt, iterations, keylen) {