diff --git a/lib/bcoin/bip151.js b/lib/bcoin/bip151.js
index a904742d..92e412e3 100644
--- a/lib/bcoin/bip151.js
+++ b/lib/bcoin/bip151.js
@@ -80,7 +80,8 @@ function BIP151Stream(cipher, key) {
 
   this.pending = [];
   this.total = 0;
-  this.waiting = 0;
+  this.waiting = 4;
+  this.hasSize = false;
 }
 
 utils.inherits(BIP151Stream, EventEmitter);
@@ -178,7 +179,7 @@ BIP151Stream.prototype.sequence = function sequence() {
  */
 
 BIP151Stream.prototype.update = function update() {
-  this.iv.writeUInt32LE(this.seq, 4, true);
+  this.iv.writeUInt32LE(this.seq, 0, true);
   return this.iv;
 };
 
@@ -267,89 +268,101 @@ BIP151Stream.prototype.verify = function verify(tag) {
 };
 
 /**
- * Parse a ciphertext payload chunk.
+ * Parse ciphertext data and split into chunks.
  * Potentially emits a `packet` event.
  * @param {Buffer} data
  */
 
 BIP151Stream.prototype.feed = function feed(data) {
-  var chunk, size, payload, tag, p, cmd, body;
+  var chunk, off, len;
 
-  while (data.length) {
-    if (!this.waiting) {
-      this.total += data.length;
-      this.pending.push(data);
+  this.total += data.length;
+  this.pending.push(data);
 
-      if (this.total < 4)
-        break;
+  while (this.total >= this.waiting) {
+    chunk = new Buffer(this.waiting);
+    off = 0;
+    len = 0;
 
-      chunk = concat(this.pending);
-
-      this.total = 0;
-      this.pending.length = 0;
-
-      size = this.decryptSize(chunk);
-      data = chunk.slice(4);
-
-      // Allow 3 batched packets of max message size (12mb).
-      // Not technically standard, but this protects us
-      // from buffering tons of data due to either an
-      // potential dos'er or a cipher state mismatch.
-      // Note that 6 is the minimum size:
-      // cmd=varint(1) string(1) length(4) data(0)
-      if (size < 6 || size > constants.MAX_MESSAGE * 3) {
-        this.emit('error', new Error('Bad packet size.'));
-        continue;
-      }
-
-      this.waiting = size + 16;
-
-      continue;
+    while (off < chunk.length) {
+      len = this.pending[0].copy(chunk, off);
+      if (len === this.pending[0].length)
+        this.pending.shift();
+      else
+        this.pending[0] = this.pending[0].slice(len);
+      off += len;
     }
 
-    this.total += data.length;
-    this.pending.push(data);
+    assert.equal(off, chunk.length);
 
-    if (this.total < this.waiting)
-      break;
+    this.total -= chunk.length;
+    this.parse(chunk);
+  }
+};
 
-    chunk = concat(this.pending);
-    payload = chunk.slice(0, this.waiting - 16);
-    tag = chunk.slice(this.waiting - 16, this.waiting);
-    data = chunk.slice(this.waiting);
+/**
+ * Parse a ciphertext payload chunk.
+ * Potentially emits a `packet` event.
+ * @param {Buffer} data
+ */
 
-    this.total = 0;
-    this.pending.length = 0;
-    this.waiting = 0;
+BIP151Stream.prototype.parse = function parse(data) {
+  var size, payload, tag, p, cmd, body;
 
-    // Authenticate payload before decrypting.
-    // This ensures the cipher state isn't altered
-    // if the payload integrity has been compromised.
-    this.auth(payload);
-    this.finish();
+  if (!this.hasSize) {
+    size = this.decryptSize(data);
 
-    if (!this.verify(tag)) {
-      this.sequence();
-      this.emit('error', new Error('Bad tag.'));
-      continue;
+    // Allow 3 batched packets of max message size (12mb).
+    // Not technically standard, but this protects us
+    // from buffering tons of data due to either an
+    // potential dos'er or a cipher state mismatch.
+    // Note that 6 is the minimum size:
+    // cmd=varint(1) string(1) length(4) data(0)
+    if (size < 6 || size > constants.MAX_MESSAGE * 3) {
+      this.waiting = 4;
+      this.emit('error', new Error('Bad packet size.'));
+      return;
     }
 
-    this.decrypt(payload);
+    this.hasSize = true;
+    this.waiting = size + 16;
+
+    return;
+  }
+
+  payload = data.slice(0, this.waiting - 16);
+  tag = data.slice(this.waiting - 16, this.waiting);
+
+  this.hasSize = false;
+  this.waiting = 4;
+
+  // Authenticate payload before decrypting.
+  // This ensures the cipher state isn't altered
+  // if the payload integrity has been compromised.
+  this.auth(payload);
+  this.finish();
+
+  if (!this.verify(tag)) {
     this.sequence();
+    this.emit('error', new Error('Bad tag.'));
+    return;
+  }
 
-    p = bcoin.reader(payload, true);
+  this.decrypt(payload);
+  this.sequence();
 
-    while (p.left()) {
-      try {
-        cmd = p.readVarString('ascii');
-        body = p.readBytes(p.readU32());
-      } catch (e) {
-        this.emit('error', e);
-        break;
-      }
+  p = bcoin.reader(payload, true);
 
-      this.emit('packet', cmd, body);
+  while (p.left()) {
+    try {
+      cmd = p.readVarString('ascii');
+      body = p.readBytes(p.readU32());
+    } catch (e) {
+      this.emit('error', e);
+      return;
     }
+
+    this.emit('packet', cmd, body);
   }
 };
 
@@ -626,16 +639,6 @@ BIP151.prototype.packet = function packet(cmd, body) {
   return this.output.packet(cmd, body);
 };
 
-/*
- * Helpers
- */
-
-function concat(buffers) {
-  return buffers.length > 1
-    ? Buffer.concat(buffers)
-    : buffers[0];
-}
-
 /*
  * Expose
  */
diff --git a/lib/bcoin/protocol/parser.js b/lib/bcoin/protocol/parser.js
index 89a2cddf..fe801167 100644
--- a/lib/bcoin/protocol/parser.js
+++ b/lib/bcoin/protocol/parser.js
@@ -93,9 +93,7 @@ Parser.prototype.feed = function feed(data) {
   this.pending.push(data);
 
   while (this.total >= this.waiting) {
-    // Concat chunks
     chunk = new Buffer(this.waiting);
-
     off = 0;
     len = 0;
 
@@ -110,7 +108,6 @@ Parser.prototype.feed = function feed(data) {
 
     assert.equal(off, chunk.length);
 
-    // Slice buffers
     this.total -= chunk.length;
     this.parse(chunk);
   }
diff --git a/lib/bcoin/workers.js b/lib/bcoin/workers.js
index f00a27b4..cbf853a0 100644
--- a/lib/bcoin/workers.js
+++ b/lib/bcoin/workers.js
@@ -951,57 +951,83 @@ function Parser() {
 utils.inherits(Parser, EventEmitter);
 
 Parser.prototype.feed = function feed(data) {
-  var chunk, header, body;
+  var chunk, off, len;
 
-  while (data) {
-    this.total += data.length;
-    this.pending.push(data);
-    data = null;
-
-    if (this.total < this.waiting)
-      break;
-
-    chunk = concat(this.pending);
-
-    if (chunk.length > this.waiting) {
-      data = chunk.slice(this.waiting);
-      chunk = chunk.slice(0, this.waiting);
-    }
-
-    if (!this.header) {
-      this.header = this.parseHeader(chunk);
-      this.waiting = this.header.size;
-      this.pending.length = 0;
-      this.total = 0;
-
-      if (this.header.magic !== 0xdeadbeef) {
-        this.header = null;
-        this.waiting = 12;
-        this.emit('error', new Error('Bad magic number.'));
-        continue;
-      }
+  this.total += data.length;
+  this.pending.push(data);
 
+  while (this.total >= this.waiting) {
+    if (this.waiting === 0) {
+      this.parse(new Buffer(0));
       continue;
     }
 
-    header = this.header;
-
-    this.pending.length = 0;
-    this.total = 0;
-    this.waiting = 12;
-    this.header = null;
-
-    try {
-      body = this.parseBody(chunk);
-    } catch (e) {
-      this.emit('error', e);
+    if (this.pending[0].length > this.waiting) {
+      chunk = this.pending[0].slice(0, this.waiting);
+      this.pending[0] = this.pending[0].slice(this.waiting);
+      this.total -= chunk.length;
+      this.parse(chunk);
       continue;
     }
 
-    this.emit('packet', header.job, body);
+    if (this.pending[0].length === this.waiting) {
+      chunk = this.pending.shift();
+      this.total -= chunk.length;
+      this.parse(chunk);
+      continue;
+    }
+
+    chunk = new Buffer(this.waiting);
+    off = 0;
+    len = 0;
+
+    while (off < chunk.length) {
+      len = this.pending[0].copy(chunk, off);
+      if (len === this.pending[0].length)
+        this.pending.shift();
+      else
+        this.pending[0] = this.pending[0].slice(len);
+      off += len;
+    }
+
+    assert.equal(off, chunk.length);
+
+    this.total -= chunk.length;
+    this.parse(chunk);
   }
 };
 
+Parser.prototype.parse = function parse(data) {
+  var header, body;
+
+  if (!this.header) {
+    header = this.parseHeader(data);
+
+    if (header.magic !== 0xdeadbeef) {
+      this.emit('error', new Error('Bad magic number.'));
+      return;
+    }
+
+    this.header = header;
+    this.waiting = header.size;
+
+    return;
+  }
+
+  header = this.header;
+  this.waiting = 12;
+  this.header = null;
+
+  try {
+    body = this.parseBody(data);
+  } catch (e) {
+    this.emit('error', e);
+    return;
+  }
+
+  this.emit('packet', header.job, body);
+};
+
 Parser.prototype.parseHeader = function parseHeader(data) {
   return {
     magic: data.readUInt32LE(0, true),
@@ -1107,12 +1133,6 @@ function fromError(err) {
   return [err.message, err.stack + '', err.type];
 }
 
-function concat(buffers) {
-  return buffers.length > 1
-    ? Buffer.concat(buffers)
-    : buffers[0];
-}
-
 /*
  * Expose
  */