feat: implmented first internal functions for KMS service

backend/src/lib/crypto/cipher/cipher.ts

@@ -0,0 +1,49 @@
+import crypto from "crypto";
+
+import { SymmetricEncryption, TSymmetricEncryptionFns } from "./types";
+
+const getIvLength = () => {
+  return 12;
+};
+
+const getTagLength = () => {
+  return 16;
+};
+
+export const symmetricCipherService = (type: SymmetricEncryption): TSymmetricEncryptionFns => {
+  const IV_LENGTH = getIvLength();
+  const TAG_LENGTH = getTagLength();
+
+  const encrypt = (text: Buffer, key: Buffer) => {
+    const iv = crypto.randomBytes(IV_LENGTH);
+    const cipher = crypto.createCipheriv(type, key, iv);
+
+    let encrypted = cipher.update(text);
+    encrypted = Buffer.concat([encrypted, cipher.final()]);
+
+    // Get the authentication tag
+    const tag = cipher.getAuthTag();
+
+    // Concatenate IV, encrypted text, and tag into a single buffer
+    const ciphertextBlob = Buffer.concat([iv, encrypted, tag]);
+    return ciphertextBlob;
+  };
+
+  const decrypt = (ciphertextBlob: Buffer, key: Buffer) => {
+    // Extract the IV, encrypted text, and tag from the buffer
+    const iv = ciphertextBlob.subarray(0, IV_LENGTH);
+    const tag = ciphertextBlob.subarray(-TAG_LENGTH);
+    const encrypted = ciphertextBlob.subarray(IV_LENGTH, -TAG_LENGTH);
+
+    const decipher = crypto.createDecipheriv(type, key, iv);
+    decipher.setAuthTag(tag);
+
+    const decrypted = Buffer.concat([decipher.update(encrypted), decipher.final()]);
+    return decrypted;
+  };
+
+  return {
+    encrypt,
+    decrypt
+  };
+};

backend/src/lib/crypto/cipher/index.ts

@@ -0,0 +1,2 @@
+export { symmetricCipherService } from "./cipher";
+export { SymmetricEncryption } from "./types";

backend/src/lib/crypto/cipher/types.ts

@@ -0,0 +1,9 @@
+export enum SymmetricEncryption {
+  AES_GCM_256 = "aes-256-gcm",
+  AES_GCM_128 = "aes-128-gcm"
+}
+
+export type TSymmetricEncryptionFns = {
+  encrypt: (text: Buffer, key: Buffer) => Buffer;
+  decrypt: (blob: Buffer, key: Buffer) => Buffer;
+};

backend/src/lib/crypto/encryption.ts

@@ -11,6 +11,8 @@ import { getConfig } from "../config/env";
 export const decodeBase64 = (s: string) => naclUtils.decodeBase64(s);
 export const encodeBase64 = (u: Uint8Array) => naclUtils.encodeBase64(u);
 
+export const randomSecureBytes = (length = 32) => crypto.randomBytes(length);
+
 export type TDecryptSymmetricInput = {
   ciphertext: string;
   iv: string;

backend/src/lib/crypto/index.ts

@@ -9,7 +9,8 @@ export {
   encryptAsymmetric,
   encryptSymmetric,
   encryptSymmetric128BitHexKeyUTF8,
-  generateAsymmetricKeyPair
+  generateAsymmetricKeyPair,
+  randomSecureBytes
 } from "./encryption";
 export {
   decryptIntegrationAuths,

backend/src/lib/zod/index.ts

@@ -7,3 +7,7 @@ export const zpStr = <T extends ZodTypeAny>(schema: T, opt: { stripNull: boolean
     if (typeof val !== "string") return val;
     return val.trim() || undefined;
   }, schema);
+
+export const zodBuffer = z.custom<Buffer>((data) => Buffer.isBuffer(data) || data instanceof Uint8Array, {
+  message: "Expected binary data (Buffer Or Uint8Array)"
+});