Attempt to curb the combinatorial explosion

web/packages/base/crypto/ente.ts

@@ -142,7 +142,7 @@ export const encryptMetadataJSON = async (r: EncryptJSON) =>
 
 /**
  * Decrypt arbitrary data, provided as a base64 string, using the given key and
- * the provided nonce.
+ * the provided nonce, and return the base64
  *
  * This is the sibling of {@link encryptBoxB64}.
  *

web/packages/base/crypto/libsodium.ts

@@ -12,10 +12,12 @@ import { mergeUint8Arrays } from "@/utils/array";
 import { CustomError } from "@ente/shared/error";
 import sodium, { type StateAddress } from "libsodium-wrappers";
 import type {
+    BytesOrB64,
     DecryptBlobBytes,
     DecryptBoxBytes,
     EncryptBytes,
     EncryptedBlobBytes,
+    EncryptedBox2,
     EncryptedBoxBytes,
 } from "./types";
 
@@ -342,6 +344,29 @@ export const decryptBox = async ({
     );
 };
 
+/**
+ * If the provided {@link bob} ("Bytes or B64 string") is already a
+ * {@link Uint8Array}, return it unchanged, otherwise convert the base64 string
+ * into bytes and return those.
+ */
+const bytes = async (bob: BytesOrB64) =>
+    typeof bob == "string" ? fromB64(bob) : bob;
+
+/**
+ * Decrypt the result of {@link encryptBox}.
+ */
+export const decryptBox2 = async (
+    { encryptedData, nonce }: EncryptedBox2,
+    key: BytesOrB64,
+): Promise<Uint8Array> => {
+    await sodium.ready;
+    return sodium.crypto_secretbox_open_easy(
+        await bytes(encryptedData),
+        await bytes(nonce),
+        await bytes(key),
+    );
+};
+
 /**
  * Decrypt the result of {@link encryptBlob}.
  */

web/packages/base/crypto/types.ts

@@ -149,6 +149,34 @@ export interface DecryptBoxBytes {
     keyB64: string;
 }
 
+/**
+ * Data provided either as bytes ({@link Uint8Array}) or their base64 string representation.
+ */
+export type BytesOrB64 = Uint8Array | string;
+
+/**
+ * A decryption request to decrypt data encrypted using the secretbox APIs.
+ *
+ * See: [Note: 3 forms of encryption (Box | Blob | Stream)].
+ */
+export interface EncryptedBox2 {
+    /**
+     * The data to decrypt.
+     */
+    encryptedData: BytesOrB64;
+    /**
+     * The nonce that was used during encryption.
+     *
+     * The nonce is required to decrypt the data, but it does not need to be
+     * kept secret.
+     */
+    nonce: BytesOrB64;
+    /**
+     * The encryption key.
+     */
+    key: BytesOrB64;
+}
+
 /**
  * A variant of {@link DecryptBoxBytes} with the encrypted Blob's data as a
  * base64 encoded string.