diff --git a/package.json b/package.json
index 241b102..1f6f13d 100644
--- a/package.json
+++ b/package.json
@@ -15,10 +15,12 @@
     "node": {
       "module": "./src/mjs/index.js",
       "require": "./src/cjs/index.cjs",
-      "import": "./src/mjs/index.js"
+      "import": "./src/mjs/index.js",
+      "types": "./src/cjs/index.d.ts"
     },
     "browser": "./src/mjs/browser.js",
-    "default": "./src/mjs/browser.js"
+    "default": "./src/mjs/browser.js",
+    "types": "./src/cjs/index.d.ts"
   },
   "types": "src/cjs/index.d.ts",
   "type": "module",
diff --git a/src/cjs/browser.cjs b/src/cjs/browser.cjs
index 24ce7e8..8c1facf 100644
--- a/src/cjs/browser.cjs
+++ b/src/cjs/browser.cjs
@@ -1,6 +1,6 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.readUInt64 = exports.readUInt32 = exports.readUInt16 = exports.readUInt8 = exports.writeUInt64 = exports.writeUInt32 = exports.writeUInt16 = exports.writeUInt8 = exports.compare = exports.fromHex = exports.toHex = exports.toUtf8 = void 0;
+exports.readUInt64 = exports.readUInt32 = exports.readUInt16 = exports.readUInt8 = exports.writeUInt64 = exports.writeUInt32 = exports.writeUInt16 = exports.writeUInt8 = exports.compare = exports.fromBase64 = exports.toBase64 = exports.fromHex = exports.toHex = exports.concat = exports.fromUtf8 = exports.toUtf8 = void 0;
 const HEX_STRINGS = "0123456789abcdefABCDEF";
 const HEX_CODES = HEX_STRINGS.split("").map((c) => c.codePointAt(0));
 const HEX_CODEPOINTS = Array(256)
@@ -17,6 +17,21 @@ function toUtf8(bytes) {
     return DECODER.decode(bytes);
 }
 exports.toUtf8 = toUtf8;
+function fromUtf8(s) {
+    return ENCODER.encode(s);
+}
+exports.fromUtf8 = fromUtf8;
+function concat(arrays) {
+    const totalLength = arrays.reduce((a, b) => a + b.length, 0);
+    const result = new Uint8Array(totalLength);
+    let offset = 0;
+    for (const array of arrays) {
+        result.set(array, offset);
+        offset += array.length;
+    }
+    return result;
+}
+exports.concat = concat;
 // There are two implementations.
 // One optimizes for length of the bytes, and uses TextDecoder.
 // One optimizes for iteration count, and appends strings.
@@ -60,6 +75,19 @@ function fromHex(hexString) {
     return i === resultBytes.length ? resultBytes : resultBytes.slice(0, i);
 }
 exports.fromHex = fromHex;
+function toBase64(bytes) {
+    return btoa(String.fromCharCode(...bytes));
+}
+exports.toBase64 = toBase64;
+function fromBase64(base64) {
+    const binaryString = atob(base64);
+    const bytes = new Uint8Array(binaryString.length);
+    for (let i = 0; i < binaryString.length; i++) {
+        bytes[i] = binaryString.charCodeAt(i);
+    }
+    return bytes;
+}
+exports.fromBase64 = fromBase64;
 // Same behavior as Buffer.compare()
 function compare(v1, v2) {
     const minLength = Math.min(v1.length, v2.length);
diff --git a/src/cjs/index.cjs b/src/cjs/index.cjs
index 597469a..8665c71 100644
--- a/src/cjs/index.cjs
+++ b/src/cjs/index.cjs
@@ -1,10 +1,18 @@
 "use strict";
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.readUInt64 = exports.readUInt32 = exports.readUInt16 = exports.readUInt8 = exports.writeUInt64 = exports.writeUInt32 = exports.writeUInt16 = exports.writeUInt8 = exports.compare = exports.fromHex = exports.toHex = exports.toUtf8 = void 0;
+exports.readUInt64 = exports.readUInt32 = exports.readUInt16 = exports.readUInt8 = exports.writeUInt64 = exports.writeUInt32 = exports.writeUInt16 = exports.writeUInt8 = exports.compare = exports.fromBase64 = exports.toBase64 = exports.fromHex = exports.toHex = exports.concat = exports.fromUtf8 = exports.toUtf8 = void 0;
 function toUtf8(bytes) {
     return Buffer.from(bytes || []).toString();
 }
 exports.toUtf8 = toUtf8;
+function fromUtf8(s) {
+    return Uint8Array.from(Buffer.from(s || "", "utf8"));
+}
+exports.fromUtf8 = fromUtf8;
+function concat(arrays) {
+    return Uint8Array.from(Buffer.concat(arrays));
+}
+exports.concat = concat;
 function toHex(bytes) {
     return Buffer.from(bytes || []).toString("hex");
 }
@@ -13,6 +21,14 @@ function fromHex(hexString) {
     return Uint8Array.from(Buffer.from(hexString || "", "hex"));
 }
 exports.fromHex = fromHex;
+function toBase64(bytes) {
+    return Buffer.from(bytes).toString("base64");
+}
+exports.toBase64 = toBase64;
+function fromBase64(base64) {
+    return Uint8Array.from(Buffer.from(base64 || "", "base64"));
+}
+exports.fromBase64 = fromBase64;
 function compare(v1, v2) {
     return Buffer.from(v1).compare(Buffer.from(v2));
 }
diff --git a/src/cjs/index.d.ts b/src/cjs/index.d.ts
index d618b5b..5cbe104 100644
--- a/src/cjs/index.d.ts
+++ b/src/cjs/index.d.ts
@@ -1,6 +1,10 @@
 export declare function toUtf8(bytes: Uint8Array): string;
+export declare function fromUtf8(s: string): Uint8Array;
+export declare function concat(arrays: Uint8Array[]): Uint8Array;
 export declare function toHex(bytes: Uint8Array): string;
 export declare function fromHex(hexString: string): Uint8Array;
+export declare function toBase64(bytes: Uint8Array): string;
+export declare function fromBase64(base64: string): Uint8Array;
 export declare type CompareResult = -1 | 0 | 1;
 export declare function compare(v1: Uint8Array, v2: Uint8Array): CompareResult;
 export declare type endian = "LE" | "BE" | "le" | "be";
diff --git a/src/mjs/browser.js b/src/mjs/browser.js
index 171ab80..aaab7e4 100644
--- a/src/mjs/browser.js
+++ b/src/mjs/browser.js
@@ -13,6 +13,19 @@ const DECODER = new TextDecoder();
 export function toUtf8(bytes) {
     return DECODER.decode(bytes);
 }
+export function fromUtf8(s) {
+    return ENCODER.encode(s);
+}
+export function concat(arrays) {
+    const totalLength = arrays.reduce((a, b) => a + b.length, 0);
+    const result = new Uint8Array(totalLength);
+    let offset = 0;
+    for (const array of arrays) {
+        result.set(array, offset);
+        offset += array.length;
+    }
+    return result;
+}
 // There are two implementations.
 // One optimizes for length of the bytes, and uses TextDecoder.
 // One optimizes for iteration count, and appends strings.
@@ -54,6 +67,17 @@ export function fromHex(hexString) {
     }
     return i === resultBytes.length ? resultBytes : resultBytes.slice(0, i);
 }
+export function toBase64(bytes) {
+    return btoa(String.fromCharCode(...bytes));
+}
+export function fromBase64(base64) {
+    const binaryString = atob(base64);
+    const bytes = new Uint8Array(binaryString.length);
+    for (let i = 0; i < binaryString.length; i++) {
+        bytes[i] = binaryString.charCodeAt(i);
+    }
+    return bytes;
+}
 // Same behavior as Buffer.compare()
 export function compare(v1, v2) {
     const minLength = Math.min(v1.length, v2.length);
diff --git a/src/mjs/index.js b/src/mjs/index.js
index 53004d5..8e41336 100644
--- a/src/mjs/index.js
+++ b/src/mjs/index.js
@@ -1,12 +1,24 @@
 export function toUtf8(bytes) {
     return Buffer.from(bytes || []).toString();
 }
+export function fromUtf8(s) {
+    return Uint8Array.from(Buffer.from(s || "", "utf8"));
+}
+export function concat(arrays) {
+    return Uint8Array.from(Buffer.concat(arrays));
+}
 export function toHex(bytes) {
     return Buffer.from(bytes || []).toString("hex");
 }
 export function fromHex(hexString) {
     return Uint8Array.from(Buffer.from(hexString || "", "hex"));
 }
+export function toBase64(bytes) {
+    return Buffer.from(bytes).toString("base64");
+}
+export function fromBase64(base64) {
+    return Uint8Array.from(Buffer.from(base64 || "", "base64"));
+}
 export function compare(v1, v2) {
     return Buffer.from(v1).compare(Buffer.from(v2));
 }
diff --git a/ts_src/browser.ts b/ts_src/browser.ts
index f8b6c7f..b2bcad5 100644
--- a/ts_src/browser.ts
+++ b/ts_src/browser.ts
@@ -15,6 +15,21 @@ export function toUtf8(bytes: Uint8Array): string {
   return DECODER.decode(bytes);
 }
 
+export function fromUtf8(s: string): Uint8Array {
+  return ENCODER.encode(s);
+}
+
+export function concat(arrays: Uint8Array[]): Uint8Array {
+  const totalLength = arrays.reduce((a, b) => a + b.length, 0);
+  const result = new Uint8Array(totalLength);
+  let offset = 0;
+  for (const array of arrays) {
+    result.set(array, offset);
+    offset += array.length;
+  }
+  return result;
+}
+
 // There are two implementations.
 // One optimizes for length of the bytes, and uses TextDecoder.
 // One optimizes for iteration count, and appends strings.
@@ -58,6 +73,19 @@ export function fromHex(hexString: string): Uint8Array {
   return i === resultBytes.length ? resultBytes : resultBytes.slice(0, i);
 }
 
+export function toBase64(bytes: Uint8Array): string {
+  return btoa(String.fromCharCode(...bytes));
+}
+
+export function fromBase64(base64: string): Uint8Array {
+  const binaryString = atob(base64);
+  const bytes = new Uint8Array(binaryString.length);
+  for (let i = 0; i < binaryString.length; i++) {
+    bytes[i] = binaryString.charCodeAt(i);
+  }
+  return bytes;
+}
+
 export type CompareResult = -1 | 0 | 1;
 // Same behavior as Buffer.compare()
 export function compare(v1: Uint8Array, v2: Uint8Array): CompareResult {
diff --git a/ts_src/index.ts b/ts_src/index.ts
index cd5cbeb..d69ffbb 100644
--- a/ts_src/index.ts
+++ b/ts_src/index.ts
@@ -2,6 +2,14 @@ export function toUtf8(bytes: Uint8Array): string {
   return Buffer.from(bytes || []).toString();
 }
 
+export function fromUtf8(s: string): Uint8Array {
+  return Uint8Array.from(Buffer.from(s || "", "utf8"));
+}
+
+export function concat(arrays: Uint8Array[]): Uint8Array {
+  return Uint8Array.from(Buffer.concat(arrays));
+}
+
 export function toHex(bytes: Uint8Array): string {
   return Buffer.from(bytes || []).toString("hex");
 }
@@ -10,6 +18,14 @@ export function fromHex(hexString: string): Uint8Array {
   return Uint8Array.from(Buffer.from(hexString || "", "hex"));
 }
 
+export function toBase64(bytes: Uint8Array): string {
+  return Buffer.from(bytes).toString("base64");
+}
+
+export function fromBase64(base64: string): Uint8Array {
+  return Uint8Array.from(Buffer.from(base64 || "", "base64"));
+}
+
 export type CompareResult = -1 | 0 | 1;
 export function compare(v1: Uint8Array, v2: Uint8Array): CompareResult {
   return Buffer.from(v1).compare(Buffer.from(v2)) as CompareResult;
diff --git a/ts_src/tests.spec.ts b/ts_src/tests.spec.ts
index ef95876..d92aaf0 100644
--- a/ts_src/tests.spec.ts
+++ b/ts_src/tests.spec.ts
@@ -53,6 +53,12 @@ describe(`Uint8Array tools`, () => {
         expect(tools.toUtf8(longBytes2)).toEqual(longUtf8);
         expect((tools.toUtf8 as any)()).toEqual("");
       });
+      it("should read utf8 with fromUtf8", () => {
+        expect(tools.fromUtf8(utf8)).toEqual(bytes3);
+        expect(tools.fromUtf8(str)).toEqual(testBytes);
+        expect(tools.fromUtf8(longUtf8)).toEqual(longBytes2);
+        expect((tools.fromUtf8 as any)()).toEqual(f([]));
+      });
       it(`should compare Uint8Arrays`, () => {
         expect(tools.compare(bytes, bytes2)).toBe(-1);
         expect(tools.compare(bytes, bytes)).toBe(0);
@@ -62,6 +68,71 @@ describe(`Uint8Array tools`, () => {
         expect(tools.compare(bytes2, bytes2LargerLeft)).toBe(1);
         expect(tools.compare(bytes2LargerLeft, bytes2)).toBe(-1);
       });
+      it("should concat Uint8Arrays", () => {
+        const fixtures = [
+          [new Uint8Array([]), new Uint8Array([])],
+          [new Uint8Array([1]), new Uint8Array([1])],
+          [new Uint8Array([])],
+          [new Uint8Array()],
+          [...new Array(1000)].map(() => new Uint8Array([123])),
+        ];
+
+        for (const fixture of fixtures) {
+          expect(new Uint8Array(Buffer.concat(fixture))).toEqual(
+            tools.concat(fixture)
+          );
+        }
+      });
+      it("should read from base64", () => {
+        const fixtures = [
+          Buffer.from("").toString("base64"),
+          Buffer.from("a").toString("base64"),
+          Buffer.from("ab").toString("base64"),
+          Buffer.from("abc").toString("base64"),
+          Buffer.from("abcd").toString("base64"),
+          Buffer.from("abcde").toString("base64"),
+          Buffer.from("abcdef").toString("base64"),
+          Buffer.from("abcdefg").toString("base64"),
+          Buffer.from("abcdefgh").toString("base64"),
+          Buffer.from("abcdefghi").toString("base64"),
+          Buffer.from("abcdefghij").toString("base64"),
+          Buffer.from("abcdefghijk").toString("base64"),
+          Buffer.from("abcdefghijkl").toString("base64"),
+          Buffer.from("abcdefghijklm").toString("base64"),
+          Buffer.from("abcdefghijklmn").toString("base64"),
+        ];
+
+        for (const fixture of fixtures) {
+          expect(tools.fromBase64(fixture)).toEqual(
+            Uint8Array.from(Buffer.from(fixture, "base64"))
+          );
+        }
+      });
+
+      it("should write to base64", () => {
+        const fixtures = [
+          Buffer.from("").toString("base64"),
+          Buffer.from("a").toString("base64"),
+          Buffer.from("ab").toString("base64"),
+          Buffer.from("abc").toString("base64"),
+          Buffer.from("abcd").toString("base64"),
+          Buffer.from("abcde").toString("base64"),
+          Buffer.from("abcdef").toString("base64"),
+          Buffer.from("abcdefg").toString("base64"),
+          Buffer.from("abcdefgh").toString("base64"),
+          Buffer.from("abcdefghi").toString("base64"),
+          Buffer.from("abcdefghij").toString("base64"),
+          Buffer.from("abcdefghijk").toString("base64"),
+          Buffer.from("abcdefghijkl").toString("base64"),
+          Buffer.from("abcdefghijklm").toString("base64"),
+          Buffer.from("abcdefghijklmn").toString("base64"),
+        ];
+
+        for (const fixture of fixtures) {
+          expect(tools.toBase64(tools.fromBase64(fixture))).toEqual(fixture);
+        }
+      });
+
       it("should writeUint8", () => {
         const hexs = ["03", "fd"];