diff --git a/src/core/operations/BLAKE2b.mjs b/src/core/operations/BLAKE2b.mjs
index 7124cd52..62709a93 100644
--- a/src/core/operations/BLAKE2b.mjs
+++ b/src/core/operations/BLAKE2b.mjs
@@ -36,6 +36,11 @@ class BLAKE2b extends Operation {
                 "name": "Output Encoding",
                 "type": "option",
                 "value": ["Hex", "Base64", "Raw"]
+            }, {
+                "name": "Key",
+                "type": "toggleString",
+                "value": "",
+                "toggleValues": ["UTF8", "Decimal", "Base64", "Hex", "Latin1"]
             }
         ];
     }
@@ -47,14 +52,19 @@ class BLAKE2b extends Operation {
      */
     run(input, args) {
         const [outSize, outFormat] = args;
-
+        let key = Utils.convertToByteArray(args[2].string || "", args[2].option);
+        if (key.length === 0){
+            key = null;
+        } else if (key.length > 64){
+            throw new OperationError(["Key cannot be greater than 64 bytes", "It is currently " + key.length +" bytes."].join("\n"));
+        }
         switch (outFormat) {
             case "Hex":
-                return blakejs.blake2bHex(input, null, outSize / 8);
+                return blakejs.blake2bHex(input, key, outSize / 8);
             case "Base64":
-                return toBase64(blakejs.blake2b(input, null, outSize / 8));
+                return toBase64(blakejs.blake2b(input, key, outSize / 8));
             case "Raw":
-                return Utils.arrayBufferToStr(blakejs.blake2b(input, null, outSize / 8).buffer);
+                return Utils.arrayBufferToStr(blakejs.blake2b(input, key, outSize / 8).buffer);
             default:
                 return new OperationError("Unsupported Output Type");
         }
diff --git a/src/core/operations/BLAKE2s.mjs b/src/core/operations/BLAKE2s.mjs
index 2e7f5dd9..0ded5eac 100644
--- a/src/core/operations/BLAKE2s.mjs
+++ b/src/core/operations/BLAKE2s.mjs
@@ -35,6 +35,12 @@ class BLAKE2s extends Operation {
                 "name": "Output Encoding",
                 "type": "option",
                 "value": ["Hex", "Base64", "Raw"]
+            },
+            {
+                "name": "Key",
+                "type": "toggleString",
+                "value": "",
+                "toggleValues": ["UTF8", "Decimal", "Base64", "Hex", "Latin1"]
             }
         ];
     }
@@ -46,13 +52,19 @@ class BLAKE2s extends Operation {
      */
     run(input, args) {
         const [outSize, outFormat] = args;
+        let key = Utils.convertToByteArray(args[2].string || "", args[2].option);
+        if (key.length === 0){
+            key = null;
+        } else if (key.length > 32){
+            throw new OperationError(["Key cannot be greater than 32 bytes", "It is currently " + key.length +" bytes."].join("\n"));
+        }
         switch (outFormat) {
             case "Hex":
-                return blakejs.blake2sHex(input, null, outSize / 8);
+                return blakejs.blake2sHex(input, key, outSize / 8);
             case "Base64":
-                return toBase64(blakejs.blake2s(input, null, outSize / 8));
+                return toBase64(blakejs.blake2s(input, key, outSize / 8));
             case "Raw":
-                return Utils.arrayBufferToStr(blakejs.blake2s(input, null, outSize / 8).buffer);
+                return Utils.arrayBufferToStr(blakejs.blake2s(input, key, outSize / 8).buffer);
             default:
                 return new OperationError("Unsupported Output Type");
         }
diff --git a/src/core/operations/GenerateAllHashes.mjs b/src/core/operations/GenerateAllHashes.mjs
index 3453302f..53a6fcf9 100644
--- a/src/core/operations/GenerateAllHashes.mjs
+++ b/src/core/operations/GenerateAllHashes.mjs
@@ -90,14 +90,14 @@ class GenerateAllHashes extends Operation {
                 "\nWhirlpool:   " + (new Whirlpool()).run(arrayBuffer, ["Whirlpool"]) +
                 "\nSSDEEP:      " + (new SSDEEP()).run(str) +
                 "\nCTPH:        " + (new CTPH()).run(str) +
-                "\nBLAKE2b-512: " + (new BLAKE2b).run(str, ["512", "Hex"]) +
-                "\nBLAKE2b-384: " + (new BLAKE2b).run(str, ["384", "Hex"]) +
-                "\nBLAKE2b-256: " + (new BLAKE2b).run(str, ["256", "Hex"]) +
-                "\nBLAKE2b-160: " + (new BLAKE2b).run(str, ["160", "Hex"]) +
-                "\nBLAKE2b-128: " + (new BLAKE2b).run(str, ["128", "Hex"]) +
-                "\nBLAKE2s-256: " + (new BLAKE2s).run(str, ["256", "Hex"]) +
-                "\nBLAKE2s-160: " + (new BLAKE2s).run(str, ["160", "Hex"]) +
-                "\nBLAKE2s-128: " + (new BLAKE2s).run(str, ["128", "Hex"]) +
+                "\nBLAKE2b-512: " + (new BLAKE2b).run(str, ["512", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2b-384: " + (new BLAKE2b).run(str, ["384", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2b-256: " + (new BLAKE2b).run(str, ["256", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2b-160: " + (new BLAKE2b).run(str, ["160", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2b-128: " + (new BLAKE2b).run(str, ["128", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2s-256: " + (new BLAKE2s).run(str, ["256", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2s-160: " + (new BLAKE2s).run(str, ["160", "Hex", {string: "", option: "UTF8"}]) +
+                "\nBLAKE2s-128: " + (new BLAKE2s).run(str, ["128", "Hex", {string: "", option: "UTF8"}]) +
                 "\n\nChecksums:" +
                 "\nFletcher-8:  " + (new Fletcher8Checksum).run(byteArray, []) +
                 "\nFletcher-16: " + (new Fletcher16Checksum).run(byteArray, []) +
diff --git a/tests/operations/tests/BLAKE2b.mjs b/tests/operations/tests/BLAKE2b.mjs
index 0c05cd76..94c4fab9 100644
--- a/tests/operations/tests/BLAKE2b.mjs
+++ b/tests/operations/tests/BLAKE2b.mjs
@@ -14,7 +14,7 @@ TestRegister.addTests([
         expectedOutput: "4386a08a265111c9896f56456e2cb61a64239115c4784cf438e36cc851221972da3fb0115f73cd02486254001f878ab1fd126aac69844ef1c1ca152379d0a9bd",
         recipeConfig: [
             { "op": "BLAKE2b",
-                "args": ["512", "Hex"] }
+                "args": ["512", "Hex", {string: "", option: "UTF8"}] }
         ]
     },
     {
@@ -23,7 +23,7 @@ TestRegister.addTests([
         expectedOutput: "4d388e82ca8f866e606b6f6f0be910abd62ad6e98c0adfc27cf35acf948986d5c5b9c18b6f47261e1e679eb98edf8e2d",
         recipeConfig: [
             { "op": "BLAKE2b",
-                "args": ["384", "Hex"] }
+                "args": ["384", "Hex", {string: "", option: "UTF8"}] }
         ]
     },
     {
@@ -32,7 +32,7 @@ TestRegister.addTests([
         expectedOutput: "1dc01772ee0171f5f614c673e3c7fa1107a8cf727bdf5a6dadb379e93c0d1d00",
         recipeConfig: [
             { "op": "BLAKE2b",
-                "args": ["256", "Hex"] }
+                "args": ["256", "Hex", {string: "", option: "UTF8"}] }
         ]
     },
     {
@@ -41,7 +41,16 @@ TestRegister.addTests([
         expectedOutput: "6a8489e6fd6e51fae12ab271ec7fc8134dd5d737",
         recipeConfig: [
             { "op": "BLAKE2b",
-                "args": ["160", "Hex"] }
+                "args": ["160", "Hex", {string: "", option: "UTF8"}] }
+        ]
+    },
+    {
+        name: "BLAKE2b: Key Test",
+        input: "message data",
+        expectedOutput: "3d363ff7401e02026f4a4687d4863ced",
+        recipeConfig: [
+            { "op": "BLAKE2b",
+                "args": ["128", "Hex", {string: "pseudorandom key", option: "UTF8"}] }
         ]
     }
 ]);
diff --git a/tests/operations/tests/BLAKE2s.mjs b/tests/operations/tests/BLAKE2s.mjs
index 80771430..09d53b6a 100755
--- a/tests/operations/tests/BLAKE2s.mjs
+++ b/tests/operations/tests/BLAKE2s.mjs
@@ -14,7 +14,7 @@ TestRegister.addTests([
         expectedOutput: "7706af019148849e516f95ba630307a2018bb7bf03803eca5ed7ed2c3c013513",
         recipeConfig: [
             { "op": "BLAKE2s",
-                "args": ["256", "Hex"] }
+                "args": ["256", "Hex", {string: "", option: "UTF8"}] }
         ]
     },
     {
@@ -23,7 +23,7 @@ TestRegister.addTests([
         expectedOutput: "0e4fcfc2ee0097ac1d72d70b595a39e09a3c7c7e",
         recipeConfig: [
             { "op": "BLAKE2s",
-                "args": ["160", "Hex"] }
+                "args": ["160", "Hex", {string: "", option: "UTF8"}] }
         ]
     },
     {
@@ -32,7 +32,16 @@ TestRegister.addTests([
         expectedOutput: "9964ee6f36126626bf864363edfa96f6",
         recipeConfig: [
             { "op": "BLAKE2s",
-                "args": ["128", "Hex"] }
+                "args": ["128", "Hex", {string: "", option: "UTF8"}] }
+        ]
+    },
+    {
+        name: "BLAKE2s: Key Test",
+        input: "Hello World",
+        expectedOutput: "9964ee6f36126626bf864363edfa96f6",
+        recipeConfig: [
+            { "op": "BLAKE2s",
+                "args": ["128", "Hex", {string: "", option: "UTF8"}] }
         ]
     }
 ]);