feat: AES cipher (#21)

Author: irfanshadikrishad

README.md

@@ -52,6 +52,7 @@ This library provides implementations of various classical and modern ciphers:
 | [The Alphabet Cipher](/docs/en/ciphers/ALPHABET.md) | Polyalphabetic                           | Yes           | Medium   | Inspired by Vigenere, Cryptography Puzzles |
 | [Salsa20](/docs/en/ciphers/SALSA20.md)              | Stream Cipher                            | Yes           | High     | Modern Cryptography, Secure Communications |
 | [ADFGVX](/docs/en/ciphers/ADFGVX.md)                | Polybius Square + Columnar Transposition | Yes           | Medium   | Used in WWI, Known for 6x6 polybius square |
+| [AES](/docs/en/ciphers/AES.md)                      | Symmetric Block Cipher                   | Yes           | High     | Also known as, Rijndael                    |
 
 More ciphers coming soon...
 

dist/Cipher.d.ts

@@ -5,6 +5,7 @@ import { Vigenere } from "./ciphers/Vigenere.js"
 import { Alphabet } from "./ciphers/Alphabet.js"
 import { Salsa20 } from "./ciphers/Salsa20.js"
 import { ADFGVX } from "./ciphers/ADFGVX.js"
+import { AES } from "./ciphers/AES.js"
 export declare abstract class Cipher {
   /**
    * Caesar cipher is a substitution cipher where each letter in the plaintext is shifted a certain number of places down the alphabet.
@@ -44,6 +45,12 @@ export declare abstract class Cipher {
    * @param codeword - 36 characters long
    */
   static ADFGVX: typeof ADFGVX
+  /**
+   * Advanced Encryption Standard (AES) is a symmetric encryption algorithm.
+   * @param key 256-bit (32 byte) key
+   * @param iv 128-bit (16 byte) initialization vector
+   */
+  static AES: typeof AES
   abstract encrypt(text: string): string | Uint8Array
   abstract decrypt(text: string | Uint8Array): string
 }

dist/ciphers/AES.d.ts

@@ -0,0 +1,8 @@
+import { Cipher } from "../Cipher.js"
+export declare class AES extends Cipher {
+  private key
+  private iv
+  constructor(key: string, iv: string)
+  encrypt(plaintext: string): string
+  decrypt(ciphertext: string): string
+}

dist/ciphers/AES.js

@@ -0,0 +1,28 @@
+import crypto from "crypto"
+import { Cipher } from "../Cipher.js"
+import { Buffer } from "buffer"
+export class AES extends Cipher {
+  constructor(key, iv) {
+    super()
+    this.key = Buffer.from(key, "hex")
+    this.iv = Buffer.from(iv, "hex")
+    if (this.key.length !== 32) {
+      throw new Error("Invalid key length: AES-256 requires a 32-byte key")
+    }
+    if (this.iv.length !== 16) {
+      throw new Error("Invalid IV length: AES requires a 16-byte IV")
+    }
+  }
+  encrypt(plaintext) {
+    const cipher = crypto.createCipheriv("aes-256-cbc", this.key, this.iv)
+    let encrypted = cipher.update(plaintext, "utf8", "hex")
+    encrypted += cipher.final("hex")
+    return encrypted
+  }
+  decrypt(ciphertext) {
+    const decipher = crypto.createDecipheriv("aes-256-cbc", this.key, this.iv)
+    let decrypted = decipher.update(ciphertext, "hex", "utf8")
+    decrypted += decipher.final("utf8")
+    return decrypted
+  }
+}

dist/index.js

@@ -6,11 +6,13 @@ import { Vigenere } from "./ciphers/Vigenere.js"
 import { Alphabet } from "./ciphers/Alphabet.js"
 import { Salsa20 } from "./ciphers/Salsa20.js"
 import { ADFGVX } from "./ciphers/ADFGVX.js"
+import { AES } from "./ciphers/AES.js"
 Cipher.Caesar = Caesar
 Cipher.Atbash = Atbash
 Cipher.Playfair = Playfair
 Cipher.Vigenere = Vigenere
 Cipher.Alphabet = Alphabet
 Cipher.Salsa20 = Salsa20
 Cipher.ADFGVX = ADFGVX
+Cipher.AES = AES
 export { Cipher }

docs/en/ciphers/AES.md

@@ -0,0 +1,21 @@
+#### AES (Advanced Encryption Standard) CIPHER
+
+The Advanced Encryption Standard, also known by its original name Rijndael, is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology in 2001.
+
+```ts
+import { Cipher } from "@irfanshadikrishad/cipher"
+
+const aes = new Cipher.AES("32bytekey", "16byteinitializebector")
+const plaintext = "hello, aes!"
+const encrypt = aes.encrypt(plaintext)
+const decrypt = aes.decrypt(encrypt)
+
+console.log(
+  `Plaintext:\t${plaintext}\nEncrypted:\t${encrypt}\nDecrypted:\t${decrypt}`
+)
+```
+
+#### Notes
+
+- This one uses `CBC (Cipher Block Chaining)`, It’s more secure than ECB and ensures each block is dependent on the previous one.
+- Using `IV (Identical Vector)`, It prevents identical plaintexts from encrypting to the same ciphertext.

src/Cipher.ts

@@ -5,6 +5,7 @@ import { Vigenere } from "./ciphers/Vigenere.js"
 import { Alphabet } from "./ciphers/Alphabet.js"
 import { Salsa20 } from "./ciphers/Salsa20.js"
 import { ADFGVX } from "./ciphers/ADFGVX.js"
+import { AES } from "./ciphers/AES.js"
 
 export abstract class Cipher {
   /**
@@ -45,6 +46,12 @@ export abstract class Cipher {
    * @param codeword - 36 characters long
    */
   static ADFGVX: typeof ADFGVX
+  /**
+   * Advanced Encryption Standard (AES) is a symmetric encryption algorithm.
+   * @param key 256-bit (32 byte) key
+   * @param iv 128-bit (16 byte) initialization vector
+   */
+  static AES: typeof AES
 
   abstract encrypt(text: string): string | Uint8Array
   abstract decrypt(text: string | Uint8Array): string

src/ciphers/AES.ts

@@ -0,0 +1,35 @@
+import crypto from "crypto"
+import { Cipher } from "../Cipher.js"
+import { Buffer } from "buffer"
+
+export class AES extends Cipher {
+  private key: Buffer
+  private iv: Buffer
+
+  constructor(key: string, iv: string) {
+    super()
+    this.key = Buffer.from(key, "hex")
+    this.iv = Buffer.from(iv, "hex")
+
+    if (this.key.length !== 32) {
+      throw new Error("Invalid key length: AES-256 requires a 32-byte key")
+    }
+    if (this.iv.length !== 16) {
+      throw new Error("Invalid IV length: AES requires a 16-byte IV")
+    }
+  }
+
+  encrypt(plaintext: string): string {
+    const cipher = crypto.createCipheriv("aes-256-cbc", this.key, this.iv)
+    let encrypted = cipher.update(plaintext, "utf8", "hex")
+    encrypted += cipher.final("hex")
+    return encrypted
+  }
+
+  decrypt(ciphertext: string): string {
+    const decipher = crypto.createDecipheriv("aes-256-cbc", this.key, this.iv)
+    let decrypted = decipher.update(ciphertext, "hex", "utf8")
+    decrypted += decipher.final("utf8")
+    return decrypted
+  }
+}

src/index.ts

@@ -6,6 +6,7 @@ import { Vigenere } from "./ciphers/Vigenere.js"
 import { Alphabet } from "./ciphers/Alphabet.js"
 import { Salsa20 } from "./ciphers/Salsa20.js"
 import { ADFGVX } from "./ciphers/ADFGVX.js"
+import { AES } from "./ciphers/AES.js"
 
 Cipher.Caesar = Caesar
 Cipher.Atbash = Atbash
@@ -14,5 +15,6 @@ Cipher.Vigenere = Vigenere
 Cipher.Alphabet = Alphabet
 Cipher.Salsa20 = Salsa20
 Cipher.ADFGVX = ADFGVX
+Cipher.AES = AES
 
 export { Cipher }

tests/aes.test.ts

@@ -0,0 +1,14 @@
+import crypto from "crypto"
+import { Cipher } from "../src/index"
+
+test("AES", () => {
+  const key = crypto.randomBytes(32).toString("hex")
+  const iv = crypto.randomBytes(16).toString("hex")
+  const aes = new Cipher.AES(key, iv)
+
+  const plaintext = "Hello, World!"
+  const ciphertext = aes.encrypt(plaintext)
+  const decrypted = aes.decrypt(ciphertext)
+
+  expect(decrypted).toBe(plaintext)
+})