diff --git a/src/packet/literal.js b/src/packet/literal.js
index d4af1f38..31d1eda1 100644
--- a/src/packet/literal.js
+++ b/src/packet/literal.js
@@ -169,7 +169,7 @@ Literal.prototype.write = function() {
   const date = util.writeDate(this.date);
   const data = this.getBytes();
 
-  return util.concatUint8Array([format, filename_length, filename, date, data]);
+  return util.concat([format, filename_length, filename, date, data]);
 };
 
 export default Literal;
diff --git a/src/packet/packetlist.js b/src/packet/packetlist.js
index 05644417..afffd8d2 100644
--- a/src/packet/packetlist.js
+++ b/src/packet/packetlist.js
@@ -86,19 +86,19 @@ List.prototype.write = function () {
         if (bufferLength >= minLength) {
           const powerOf2 = Math.min(Math.log(bufferLength) / Math.LN2 | 0, 30);
           const chunkSize = 2 ** powerOf2;
-          const bufferConcat = util.concatUint8Array([packetParser.writePartialLength(powerOf2)].concat(buffer));
+          const bufferConcat = util.concat([packetParser.writePartialLength(powerOf2)].concat(buffer));
           buffer = [bufferConcat.subarray(1 + chunkSize)];
           bufferLength = buffer[0].length;
           return bufferConcat.subarray(0, 1 + chunkSize);
         }
-      }, () => util.concatUint8Array([packetParser.writeSimpleLength(bufferLength)].concat(buffer))));
+      }, () => util.concat([packetParser.writeSimpleLength(bufferLength)].concat(buffer))));
     } else {
       arr.push(packetParser.writeHeader(this[i].tag, packetbytes.length));
       arr.push(packetbytes);
     }
   }
 
-  return util.concatUint8Array(arr);
+  return util.concat(arr);
 };
 
 /**
diff --git a/src/packet/signature.js b/src/packet/signature.js
index 7c0aeb32..c430a637 100644
--- a/src/packet/signature.js
+++ b/src/packet/signature.js
@@ -208,7 +208,7 @@ Signature.prototype.write = function () {
   }
   arr.push(this.signedHashValue);
   arr.push(this.signature);
-  return util.concatUint8Array(arr);
+  return util.concat(arr);
 };
 
 /**
@@ -237,7 +237,7 @@ Signature.prototype.sign = async function (key, data) {
   // Add hashed subpackets
   arr.push(this.write_all_sub_packets());
 
-  this.signatureData = util.concatUint8Array(arr);
+  this.signatureData = util.concat(arr);
 
   const trailer = this.calculateTrailer();
 
@@ -245,10 +245,10 @@ Signature.prototype.sign = async function (key, data) {
 
   switch (this.version) {
     case 3:
-      toHash = util.concatUint8Array([this.toSign(signatureType, data), new Uint8Array([signatureType]), util.writeDate(this.created)]);
+      toHash = util.concat([this.toSign(signatureType, data), new Uint8Array([signatureType]), util.writeDate(this.created)]);
       break;
     case 4:
-      toHash = util.concatUint8Array([this.toSign(signatureType, data), this.signatureData, trailer]);
+      toHash = util.concat([this.toSign(signatureType, data), this.signatureData, trailer]);
       break;
     default: throw new Error('Version ' + this.version + ' of the signature is unsupported.');
   }
@@ -299,7 +299,7 @@ Signature.prototype.write_all_sub_packets = function () {
   }
   if (this.revocationKeyClass !== null) {
     bytes = new Uint8Array([this.revocationKeyClass, this.revocationKeyAlgorithm]);
-    bytes = util.concatUint8Array([bytes, this.revocationKeyFingerprint]);
+    bytes = util.concat([bytes, this.revocationKeyFingerprint]);
     arr.push(write_sub_packet(sub.revocation_key, bytes));
   }
   if (!this.issuerKeyId.isNull() && this.issuerKeyVersion !== 5) {
@@ -315,7 +315,7 @@ Signature.prototype.write_all_sub_packets = function () {
       // 2 octets of value length
       bytes.push(util.writeNumber(value.length, 2));
       bytes.push(util.str_to_Uint8Array(name + value));
-      bytes = util.concatUint8Array(bytes);
+      bytes = util.concat(bytes);
       arr.push(write_sub_packet(sub.notation_data, bytes));
     });
   }
@@ -358,7 +358,7 @@ Signature.prototype.write_all_sub_packets = function () {
   if (this.signatureTargetPublicKeyAlgorithm !== null) {
     bytes = [new Uint8Array([this.signatureTargetPublicKeyAlgorithm, this.signatureTargetHashAlgorithm])];
     bytes.push(util.str_to_Uint8Array(this.signatureTargetHash));
-    bytes = util.concatUint8Array(bytes);
+    bytes = util.concat(bytes);
     arr.push(write_sub_packet(sub.signature_target, bytes));
   }
   if (this.embeddedSignature !== null) {
@@ -366,7 +366,7 @@ Signature.prototype.write_all_sub_packets = function () {
   }
   if (this.issuerFingerprint !== null) {
     bytes = [new Uint8Array([this.issuerKeyVersion]), this.issuerFingerprint];
-    bytes = util.concatUint8Array(bytes);
+    bytes = util.concat(bytes);
     arr.push(write_sub_packet(sub.issuer_fingerprint, bytes));
   }
   if (this.preferredAeadAlgorithms !== null) {
@@ -374,10 +374,10 @@ Signature.prototype.write_all_sub_packets = function () {
     arr.push(write_sub_packet(sub.preferred_aead_algorithms, bytes));
   }
 
-  const result = util.concatUint8Array(arr);
+  const result = util.concat(arr);
   const length = util.writeNumber(result.length, 2);
 
-  return util.concatUint8Array([length, result]);
+  return util.concat([length, result]);
 };
 
 /**
@@ -394,7 +394,7 @@ function write_sub_packet(type, data) {
   arr.push(packet.writeSimpleLength(data.length + 1));
   arr.push(new Uint8Array([type]));
   arr.push(data);
-  return util.concatUint8Array(arr);
+  return util.concat(arr);
 }
 
 // V4 signature sub packets
@@ -611,12 +611,12 @@ Signature.prototype.toSign = function (type, data) {
       const bytes = packet.write();
 
       if (this.version === 4) {
-        return util.concatUint8Array([this.toSign(t.key, data),
+        return util.concat([this.toSign(t.key, data),
           new Uint8Array([tag]),
           util.writeNumber(bytes.length, 4),
           bytes]);
       } else if (this.version === 3) {
-        return util.concatUint8Array([this.toSign(t.key, data),
+        return util.concat([this.toSign(t.key, data),
           bytes]);
       }
       break;
@@ -624,7 +624,7 @@ Signature.prototype.toSign = function (type, data) {
     case t.subkey_binding:
     case t.subkey_revocation:
     case t.key_binding:
-      return util.concatUint8Array([this.toSign(t.key, data), this.toSign(t.key, {
+      return util.concat([this.toSign(t.key, data), this.toSign(t.key, {
         key: data.bind
       })]);
 
@@ -653,7 +653,7 @@ Signature.prototype.calculateTrailer = function () {
     return new Uint8Array(0);
   }
   const first = new Uint8Array([4, 0xFF]); //Version, ?
-  return util.concatUint8Array([first, util.writeNumber(this.signatureData.length, 4)]);
+  return util.concat([first, util.writeNumber(this.signatureData.length, 4)]);
 };
 
 
@@ -700,7 +700,7 @@ Signature.prototype.verify = async function (key, data) {
 
   this.verified = await crypto.signature.verify(
     publicKeyAlgorithm, hashAlgorithm, mpi, key.params,
-    util.concatUint8Array([bytes, this.signatureData, trailer])
+    util.concat([bytes, this.signatureData, trailer])
   );
 
   return this.verified;
diff --git a/src/packet/sym_encrypted_aead_protected.js b/src/packet/sym_encrypted_aead_protected.js
index 821a2a86..2775ae5c 100644
--- a/src/packet/sym_encrypted_aead_protected.js
+++ b/src/packet/sym_encrypted_aead_protected.js
@@ -80,9 +80,9 @@ SymEncryptedAEADProtected.prototype.read = async function (bytes) {
  */
 SymEncryptedAEADProtected.prototype.write = function () {
   if (config.aead_protect_version === 4) {
-    return util.concatUint8Array([new Uint8Array([this.version, this.cipherAlgo, this.aeadAlgo, this.chunkSizeByte]), this.iv, this.encrypted]);
+    return util.concat([new Uint8Array([this.version, this.cipherAlgo, this.aeadAlgo, this.chunkSizeByte]), this.iv, this.encrypted]);
   }
-  return util.concatUint8Array([new Uint8Array([this.version]), this.iv, this.encrypted]);
+  return util.concat([new Uint8Array([this.version]), this.iv, this.encrypted]);
 };
 
 /**
diff --git a/src/packet/sym_encrypted_integrity_protected.js b/src/packet/sym_encrypted_integrity_protected.js
index 8bcced81..60537131 100644
--- a/src/packet/sym_encrypted_integrity_protected.js
+++ b/src/packet/sym_encrypted_integrity_protected.js
@@ -77,7 +77,7 @@ SymEncryptedIntegrityProtected.prototype.read = async function (bytes) {
 };
 
 SymEncryptedIntegrityProtected.prototype.write = function () {
-  return util.concatUint8Array([new Uint8Array([VERSION]), this.encrypted]);
+  return util.concat([new Uint8Array([VERSION]), this.encrypted]);
 };
 
 /**
@@ -91,15 +91,15 @@ SymEncryptedIntegrityProtected.prototype.encrypt = async function (sessionKeyAlg
   const bytes = this.packets.write();
   const prefixrandom = await crypto.getPrefixRandom(sessionKeyAlgorithm);
   const repeat = new Uint8Array([prefixrandom[prefixrandom.length - 2], prefixrandom[prefixrandom.length - 1]]);
-  const prefix = util.concatUint8Array([prefixrandom, repeat]);
+  const prefix = util.concat([prefixrandom, repeat]);
   const mdc = new Uint8Array([0xD3, 0x14]); // modification detection code packet
 
-  let [tohash, tohashClone] = stream.tee(util.concatUint8Array([bytes, mdc]));
-  const hash = crypto.hash.sha1(util.concatUint8Array([prefix, tohashClone]));
-  tohash = util.concatUint8Array([tohash, hash]);
+  let [tohash, tohashClone] = stream.tee(util.concat([bytes, mdc]));
+  const hash = crypto.hash.sha1(util.concat([prefix, tohashClone]));
+  tohash = util.concat([tohash, hash]);
 
   if (sessionKeyAlgorithm.substr(0, 3) === 'aes') { // AES optimizations. Native code for node, asmCrypto for browser.
-    this.encrypted = aesEncrypt(sessionKeyAlgorithm, util.concatUint8Array([prefix, tohash]), key);
+    this.encrypted = aesEncrypt(sessionKeyAlgorithm, util.concat([prefix, tohash]), key);
   } else {
     this.encrypted = crypto.cfb.encrypt(prefixrandom, sessionKeyAlgorithm, tohash, key, false);
     this.encrypted = stream.subarray(this.encrypted, 0, prefix.length + tohash.length);
@@ -130,7 +130,7 @@ SymEncryptedIntegrityProtected.prototype.decrypt = async function (sessionKeyAlg
   const encryptedPrefix = await stream.readToEnd(stream.subarray(encryptedClone, 0, crypto.cipher[sessionKeyAlgorithm].blockSize + 2));
   const prefix = crypto.cfb.mdc(sessionKeyAlgorithm, key, encryptedPrefix);
   let [bytes, bytesClone] = stream.tee(stream.subarray(decrypted, 0, -20));
-  const tohash = util.concatUint8Array([prefix, bytes]);
+  const tohash = util.concat([prefix, bytes]);
   this.hash = util.Uint8Array_to_str(await stream.readToEnd(crypto.hash.sha1(tohash)));
   const mdc = util.Uint8Array_to_str(await stream.readToEnd(stream.subarray(decryptedClone, -20)));
 
@@ -176,7 +176,7 @@ function nodeEncrypt(algo, prefix, pt, key) {
   key = new Buffer(key);
   const iv = new Buffer(new Uint8Array(crypto.cipher[algo].blockSize));
   const cipherObj = new nodeCrypto.createCipheriv('aes-' + algo.substr(3, 3) + '-cfb', key, iv);
-  const ct = cipherObj.update(new Buffer(util.concatUint8Array([prefix, pt])));
+  const ct = cipherObj.update(new Buffer(util.concat([prefix, pt])));
   return new Uint8Array(ct);
 }
 
diff --git a/src/util.js b/src/util.js
index 38ed6656..39b1ae08 100644
--- a/src/util.js
+++ b/src/util.js
@@ -282,28 +282,29 @@ export default {
   },
 
   /**
-   * Concat a list of Uint8arrays or a list of Strings
-   * @param {Array<Uint8array|String>} Array of Uint8Arrays/Strings to concatenate
-   * @returns {Uint8array|String} Concatenated array
+   * Concat a list of Uint8Arrays, Strings or Streams
+   * The caller must not mix Uint8Arrays with Strings, but may mix Streams with non-Streams.
+   * @param {Array<Uint8array|String|ReadableStream>} Array of Uint8Arrays/Strings/Streams to concatenate
+   * @returns {Uint8array|String|ReadableStream} Concatenated array
    */
-  concat: function (arrays) {
-    if (util.isUint8Array(arrays[0])) {
-      return util.concatUint8Array(arrays);
+  concat: function (list) {
+    if (list.some(util.isStream)) {
+      return stream.concat(list);
     }
-    return arrays.join('');
+    if (util.isUint8Array(list[0])) {
+      return util.concatUint8Array(list);
+    }
+    return list.join('');
   },
 
   /**
-   * Concat Uint8arrays
+   * Concat Uint8Arrays
    * @param {Array<Uint8array>} Array of Uint8Arrays to concatenate
    * @returns {Uint8array} Concatenated array
    */
   concatUint8Array: function (arrays) {
     let totalLength = 0;
     for (let i = 0; i < arrays.length; i++) {
-      if (util.isStream(arrays[i])) {
-        return stream.concat(arrays);
-      }
       if (!util.isUint8Array(arrays[i])) {
         throw new Error('concatUint8Array: Data must be in the form of a Uint8Array');
       }