diff --git a/types/bcryptjs/bcryptjs-tests.ts b/types/bcryptjs/bcryptjs-tests.ts
index cd91eb4896..2fc9f0bc0c 100644
--- a/types/bcryptjs/bcryptjs-tests.ts
+++ b/types/bcryptjs/bcryptjs-tests.ts
@@ -3,6 +3,7 @@ import bcryptjs = require("bcryptjs");
 let str: string;
 let num: number;
 let bool: boolean;
+let arr: number[];
 let error: Error;
 
 str = bcryptjs.genSaltSync();
@@ -63,3 +64,7 @@ bcryptjs.compare("string1", "string2")
 num = bcryptjs.getRounds("string");
 
 str = bcryptjs.getSalt("string");
+
+str = bcryptjs.encodeBase64([1, 2, 3, 4, 5], 5);
+
+arr = bcryptjs.decodeBase64("string", 5);
diff --git a/types/bcryptjs/index.d.ts b/types/bcryptjs/index.d.ts
index b19413c92d..f04cd68834 100644
--- a/types/bcryptjs/index.d.ts
+++ b/types/bcryptjs/index.d.ts
@@ -1,8 +1,10 @@
 // Type definitions for bcryptjs v2.4.0
 // Project: https://github.com/dcodeIO/bcrypt.js
-// Definitions by: Joshua Filby <https://github.com/Joshua-F/>, Rafael Kraut <https://github.com/RafaelKr>
+// Definitions by: Joshua Filby <https://github.com/Joshua-F/>
+//                 Rafael Kraut <https://github.com/RafaelKr>
+//                 Branislav Holý <https://github.com/branoholy>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
-
+// TypeScript Version: 2.1
 
 
 /**
@@ -103,3 +105,19 @@ export declare function getRounds(hash: string): number;
  * @return Extracted salt part
  */
 export declare function getSalt(hash: string): string;
+
+/**
+ * Encodes a byte array to base64 with up to len bytes of input, using the custom bcrypt alphabet.
+ * @function
+ * @param b Byte array
+ * @param len Maximum input length
+ */
+export declare function encodeBase64(b: Readonly<ArrayLike<number>>, len: number): string;
+
+/**
+ * Decodes a base64 encoded string to up to len bytes of output, using the custom bcrypt alphabet.
+ * @function
+ * @param s String to decode
+ * @param len Maximum output length
+ */
+export declare function decodeBase64(s: string, len: number): number[];