Revert "Remove pbkdf2Sha512Crypto and getCryptoModule"

This reverts commit 1eb7f49446 (PR #1342).

CHANGELOG.md

@@ -12,10 +12,6 @@ and this project adheres to
 - all: Add full support for Node.js 18 and run all CI tests with it ([#1240]).
 - @cosmjs/tendermint-rpc: Remove unused `index` field from `RpcTxEvent` and
   `TxEvent`. This is unset starting with Tendermint 0.34.
-- @cosmjs/crypto: The pbkdf2 implementation for old Node.js versions
-  `pbkdf2Sha512Crypto` was removed. Node.js has sufficient support for WebCrypto
-  these days and we still have a pure-JS fallback implementation. This avoids
-  unnecessary problems around importing Node.js modules. ([#1341])
 - @cosmjs/proto-signing: Make input and output of `decodePubkey` non-optional
   ([#1289]).
 - @cosmjs/stargate: Remove unnecessary address prefix argument from
@@ -31,7 +27,6 @@ and this project adheres to
 [#1289]: https://github.com/cosmos/cosmjs/issues/1289
 [#1291]: https://github.com/cosmos/cosmjs/issues/1291
 [#1329]: https://github.com/cosmos/cosmjs/pull/1329
-[#1341]: https://github.com/cosmos/cosmjs/issues/1341
 
 ## [0.29.5] - 2022-12-07
 

packages/crypto/src/pbkdf2.spec.ts

@@ -1,6 +1,13 @@
 import { fromHex, toAscii, toUtf8 } from "@cosmjs/encoding";
 
-import { getSubtle, pbkdf2Sha512, pbkdf2Sha512Noble, pbkdf2Sha512Subtle } from "./pbkdf2";
+import {
+  getCryptoModule,
+  getSubtle,
+  pbkdf2Sha512,
+  pbkdf2Sha512Crypto,
+  pbkdf2Sha512Noble,
+  pbkdf2Sha512Subtle,
+} from "./pbkdf2";
 
 interface TestVector {
   secret: Uint8Array;
@@ -139,6 +146,25 @@ describe("pbkdf2", () => {
     });
   });
 
+  describe("pbkdf2Sha512Crypto", () => {
+    it("works", async () => {
+      const crypto = await getCryptoModule();
+      if (!crypto) pending("The crypto module is not available in this environment");
+
+      {
+        const { secret, salt, iterations, keylen, expected } = botanTest;
+        const hash = await pbkdf2Sha512Crypto(crypto, secret, salt, iterations, keylen);
+        expect(hash).toEqual(expected);
+      }
+
+      for (const [index, test] of brycxTests.entries()) {
+        const { secret, salt, iterations, keylen, expected } = test;
+        const hash = await pbkdf2Sha512Crypto(crypto, secret, salt, iterations, keylen);
+        expect(hash).withContext(`brycx tests index ${index}`).toEqual(expected);
+      }
+    });
+  });
+
   describe("pbkdf2Sha512Noble", () => {
     it("works", async () => {
       {

packages/crypto/src/pbkdf2.ts

@@ -2,6 +2,27 @@ import { assert } from "@cosmjs/utils";
 import { pbkdf2Async as noblePbkdf2Async } from "@noble/hashes/pbkdf2";
 import { sha512 as nobleSha512 } from "@noble/hashes/sha512";
 
+/**
+ * Returns the Node.js crypto module when available and `undefined`
+ * otherwise.
+ *
+ * Detects an unimplemented fallback module from Webpack 5 and returns
+ * `undefined` in that case.
+ */
+export async function getCryptoModule(): Promise<any | undefined> {
+  try {
+    const crypto = await import("crypto");
+    // We get `Object{default: Object{}}` as a fallback when using
+    // `crypto: false` in Webpack 5, which we interprete as unavailable.
+    if (typeof crypto === "object" && Object.keys(crypto).length <= 1) {
+      return undefined;
+    }
+    return crypto;
+  } catch {
+    return undefined;
+  }
+}
+
 export async function getSubtle(): Promise<any | undefined> {
   // From Node.js 15 onwards, webcrypto is available in globalThis.
   // In version 15 and 16 this was stored under the webcrypto key.
@@ -47,6 +68,29 @@ export async function pbkdf2Sha512Subtle(
   );
 }
 
+export async function pbkdf2Sha512Crypto(
+  // eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+  crypto: any,
+  secret: Uint8Array,
+  salt: Uint8Array,
+  iterations: number,
+  keylen: number,
+): Promise<Uint8Array> {
+  assert(crypto, "Argument crypto is falsy");
+  assert(typeof crypto === "object", "Argument crypto is not of type object");
+  assert(typeof crypto.pbkdf2 === "function", "crypto.pbkdf2 is not a function");
+
+  return new Promise((resolve, reject) => {
+    crypto.pbkdf2(secret, salt, iterations, keylen, "sha512", (error: any, result: any) => {
+      if (error) {
+        reject(error);
+      } else {
+        resolve(Uint8Array.from(result));
+      }
+    });
+  });
+}
+
 export async function pbkdf2Sha512Noble(
   secret: Uint8Array,
   salt: Uint8Array,
@@ -69,6 +113,11 @@ export async function pbkdf2Sha512(
   if (subtle) {
     return pbkdf2Sha512Subtle(subtle, secret, salt, iterations, keylen);
   } else {
-    return pbkdf2Sha512Noble(secret, salt, iterations, keylen);
+    const crypto = await getCryptoModule();
+    if (crypto) {
+      return pbkdf2Sha512Crypto(crypto, secret, salt, iterations, keylen);
+    } else {
+      return pbkdf2Sha512Noble(secret, salt, iterations, keylen);
+    }
   }
 }