[EC-271] Refactor CryptoService - move symmetric encryption to EncryptService (#3042)

* move decryptFromBytes, decryptToBytes, and encryptToBytes from CryptoService to EncryptService
* leave redirects in CryptoService
* combine encryptService decryptFromBytes and decryptToBytes methods
* move parsing logic into EncArrayBuffer
* add tests

libs/common/spec/domain/encArrayBuffer.spec.ts

@@ -0,0 +1,76 @@
+import { EncryptionType } from "@bitwarden/common/enums/encryptionType";
+import { EncArrayBuffer } from "@bitwarden/common/models/domain/encArrayBuffer";
+
+import { makeStaticByteArray } from "../utils";
+
+describe("encArrayBuffer", () => {
+  describe("parses the buffer", () => {
+    test.each([
+      [EncryptionType.AesCbc128_HmacSha256_B64, "AesCbc128_HmacSha256_B64"],
+      [EncryptionType.AesCbc256_HmacSha256_B64, "AesCbc256_HmacSha256_B64"],
+    ])("with %c%s", (encType: EncryptionType) => {
+      const iv = makeStaticByteArray(16, 10);
+      const mac = makeStaticByteArray(32, 20);
+      // We use the minimum data length of 1 to test the boundary of valid lengths
+      const data = makeStaticByteArray(1, 100);
+
+      const array = new Uint8Array(1 + iv.byteLength + mac.byteLength + data.byteLength);
+      array.set([encType]);
+      array.set(iv, 1);
+      array.set(mac, 1 + iv.byteLength);
+      array.set(data, 1 + iv.byteLength + mac.byteLength);
+
+      const actual = new EncArrayBuffer(array.buffer);
+
+      expect(actual.encryptionType).toEqual(encType);
+      expect(actual.ivBytes).toEqualBuffer(iv);
+      expect(actual.macBytes).toEqualBuffer(mac);
+      expect(actual.dataBytes).toEqualBuffer(data);
+    });
+
+    it("with AesCbc256_B64", () => {
+      const encType = EncryptionType.AesCbc256_B64;
+      const iv = makeStaticByteArray(16, 10);
+      // We use the minimum data length of 1 to test the boundary of valid lengths
+      const data = makeStaticByteArray(1, 100);
+
+      const array = new Uint8Array(1 + iv.byteLength + data.byteLength);
+      array.set([encType]);
+      array.set(iv, 1);
+      array.set(data, 1 + iv.byteLength);
+
+      const actual = new EncArrayBuffer(array.buffer);
+
+      expect(actual.encryptionType).toEqual(encType);
+      expect(actual.ivBytes).toEqualBuffer(iv);
+      expect(actual.dataBytes).toEqualBuffer(data);
+      expect(actual.macBytes).toBeNull();
+    });
+  });
+
+  describe("throws if the buffer has an invalid length", () => {
+    test.each([
+      [EncryptionType.AesCbc128_HmacSha256_B64, 50, "AesCbc128_HmacSha256_B64"],
+      [EncryptionType.AesCbc256_HmacSha256_B64, 50, "AesCbc256_HmacSha256_B64"],
+      [EncryptionType.AesCbc256_B64, 18, "AesCbc256_B64"],
+    ])("with %c%c%s", (encType: EncryptionType, minLength: number) => {
+      // Generate invalid byte array
+      // Minus 1 to leave room for the encType, minus 1 to make it invalid
+      const invalidBytes = makeStaticByteArray(minLength - 2);
+
+      const invalidArray = new Uint8Array(1 + invalidBytes.buffer.byteLength);
+      invalidArray.set([encType]);
+      invalidArray.set(invalidBytes, 1);
+
+      expect(() => new EncArrayBuffer(invalidArray.buffer)).toThrow(
+        "Error parsing encrypted ArrayBuffer"
+      );
+    });
+  });
+
+  it("doesn't parse the buffer if the encryptionType is not supported", () => {
+    // Starting at 9 implicitly gives us an invalid encType
+    const bytes = makeStaticByteArray(50, 9);
+    expect(() => new EncArrayBuffer(bytes)).toThrow("Error parsing encrypted ArrayBuffer");
+  });
+});