1 files changed, 41 insertions, 0 deletions
diff --git a/toolkit/mozapps/extensions/internal/crypto-utils.sys.mjs b/toolkit/mozapps/extensions/internal/crypto-utils.sys.mjs
new file mode 100644
index 0000000000..d242948dfd
--- /dev/null
+++ b/toolkit/mozapps/extensions/internal/crypto-utils.sys.mjs
@@ -0,0 +1,41 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+const CryptoHash = Components.Constructor(
+  "@mozilla.org/security/hash;1",
+  "nsICryptoHash",
+  "initWithString"
+);
+
+/**
+ * Returns the string representation (hex) of the SHA256 hash of `input`.
+ *
+ * @param {string} input
+ *        The value to hash.
+ * @returns {string}
+ *          The hex representation of a SHA256 hash.
+ */
+export function computeSha256HashAsString(input) {
+  const data = new Uint8Array(new TextEncoder().encode(input));
+  const crypto = CryptoHash("sha256");
+  crypto.update(data, data.length);
+  return getHashStringForCrypto(crypto);
+}
+
+/**
+ * Returns the string representation (hex) of a given CryptoHashInstance.
+ *
+ * @param {CryptoHash} aCrypto
+ * @returns {string}
+ *          The hex representation of a SHA256 hash.
+ */
+export function getHashStringForCrypto(aCrypto) {
+  // return the two-digit hexadecimal code for a byte
+  let toHexString = charCode => ("0" + charCode.toString(16)).slice(-2);
+
+  // convert the binary hash data to a hex string.
+  let binary = aCrypto.finish(/* base64 */ false);
+  let hash = Array.from(binary, c => toHexString(c.charCodeAt(0)));
+  return hash.join("").toLowerCase();
+}