diff --git a/CHANGELOG.md b/CHANGELOG.md
index e78ce0fd3..54c232faf 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -14,6 +14,7 @@ Changes:
 - Add `stringPascalCase` utility
 - Add `isCodec` to check for Codec-like structures
 - Add `has*` detection shortcuts (e.g. `hasWasm` or `hasBuffer`)
+- Add `sha256AsU8a` util (& replace use internally)
 - Optimize for `hexToU8a` and `u8aToHex` functions
 - Optimize `u8aEq` to use `DataView` for compares
 - Align base{32, 58, 64} around (audited) `micro-base`
diff --git a/packages/util-crypto/src/bundle.ts b/packages/util-crypto/src/bundle.ts
index b8059a15f..ec9400b16 100644
--- a/packages/util-crypto/src/bundle.ts
+++ b/packages/util-crypto/src/bundle.ts
@@ -26,6 +26,7 @@ export * from './random';
 export * from './schnorrkel';
 export * from './scrypt';
 export * from './secp256k1';
+export * from './sha256';
 export * from './sha512';
 export * from './signature';
 export * from './xxhash';
diff --git a/packages/util-crypto/src/mnemonic/bip39.ts b/packages/util-crypto/src/mnemonic/bip39.ts
index 6e05fe35c..4c3788221 100644
--- a/packages/util-crypto/src/mnemonic/bip39.ts
+++ b/packages/util-crypto/src/mnemonic/bip39.ts
@@ -13,12 +13,11 @@
 //   - Remove setting of wordlist passing of wordlist in functions
 //   - Remove mnemonicToSeed (we only use the sync variant)
 
-import hash from 'hash.js';
-
 import { assert, stringToU8a, u8aToU8a } from '@polkadot/util';
 
 import { pbkdf2Encode } from '../pbkdf2';
 import { randomAsU8a } from '../random/asU8a';
+import { sha256AsU8a } from '../sha256/asU8a';
 import DEFAULT_WORDLIST from './bip39-en';
 
 const INVALID_MNEMONIC = 'Invalid mnemonic';
@@ -39,9 +38,7 @@ function bytesToBinary (bytes: number[]): string {
 
 function deriveChecksumBits (entropyBuffer: Uint8Array): string {
   return bytesToBinary(
-    Array.from(
-      hash.sha256().update(entropyBuffer).digest()
-    )
+    Array.from(sha256AsU8a(entropyBuffer))
   ).slice(0, (entropyBuffer.length * 8) / 32);
 }
 
diff --git a/packages/util-crypto/src/sha256/asU8a.spec.ts b/packages/util-crypto/src/sha256/asU8a.spec.ts
new file mode 100644
index 000000000..c4642fb92
--- /dev/null
+++ b/packages/util-crypto/src/sha256/asU8a.spec.ts
@@ -0,0 +1,37 @@
+// Copyright 2017-2021 @polkadot/util-crypto authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import { hexToU8a } from '@polkadot/util';
+
+import { sha256AsU8a } from '.';
+
+const TESTS = [
+  {
+    input: '0xe3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855',
+    output: '0x5df6e0e2761359d30a8275058e299fcc0381534545f55cf43e41983f5d4c9456'
+  },
+  {
+    input: '0x7941cb07924fdc7b710e11d98d82850e89566e1c3cb980517ffe4b430f86dfd5',
+    output: '0xe668668fa102ccd4d3cf50e4472be8426e7dc52d6d355bee8c5e2177d1de81f7'
+  },
+  {
+    input: '0x5d9a905bc3ca7c153623af0a05231960eb3f5bdd5b8b7b55ede8b2deac689d65',
+    output: '0x6721bc38e80d03f4f45f1544819d17e0c33674eb6efcddf6c6192cd78194dd9f'
+  },
+  {
+    input: '0xb0cd6528ae4d5baf7c6f0d202e7f372b6488d22b2a5bd72f794f8f1e6031b31f',
+    output: '0x353f5a030af27885aed3571cd9e2cac9f4331c51d31cef496a586496aec32256'
+  },
+  {
+    input: '0x841267bd4110e1b634e17cd019abc6ae4f9a6dd097fb063000c1615a643b5463',
+    output: '0x8174a30d921978e7055516189872cca737b49468c6bcf7fdfe59d4a54c489a1f'
+  }
+];
+
+describe('sha256AsU8a', (): void => {
+  it.each(TESTS)('creates known sha-256 hash', ({ input, output }): void => {
+    expect(
+      sha256AsU8a(hexToU8a(input))
+    ).toEqual(hexToU8a(output));
+  });
+});
diff --git a/packages/util-crypto/src/sha256/asU8a.ts b/packages/util-crypto/src/sha256/asU8a.ts
new file mode 100644
index 000000000..503d5f0dc
--- /dev/null
+++ b/packages/util-crypto/src/sha256/asU8a.ts
@@ -0,0 +1,17 @@
+// Copyright 2017-2021 @polkadot/util-crypto authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+import hash from 'hash.js';
+
+/**
+ * @name sha256AsU8a
+ * @summary Creates sha-256 hash of the input.
+ */
+export function sha256AsU8a (data: Uint8Array): Uint8Array {
+  return new Uint8Array(
+    hash
+      .sha256()
+      .update(data)
+      .digest()
+  );
+}
diff --git a/packages/util-crypto/src/sha256/index.ts b/packages/util-crypto/src/sha256/index.ts
new file mode 100644
index 000000000..cd8d178e8
--- /dev/null
+++ b/packages/util-crypto/src/sha256/index.ts
@@ -0,0 +1,8 @@
+// Copyright 2017-2021 @polkadot/util-crypto authors & contributors
+// SPDX-License-Identifier: Apache-2.0
+
+/**
+ * @summary Implements Sha-256 hashing functions for a variety of input and outputs
+ */
+
+export { sha256AsU8a } from './asU8a';