1 files changed, 34 insertions, 0 deletions
diff --git a/core/crypto/bigint.js b/core/crypto/bigint.js
new file mode 100644
index 0000000..d344326
--- /dev/null
+++ b/core/crypto/bigint.js
@@ -0,0 +1,34 @@
+export function modPow(b, e, m) {
+    let r = 1n;
+    b = b % m;
+    while (e > 0n) {
+        if ((e & 1n) === 1n) {
+            r = (r * b) % m;
+        }
+        e = e >> 1n;
+        b = (b * b) % m;
+    }
+    return r;
+}
+
+export function bigIntToU8Array(bigint, padLength=0) {
+    let hex = bigint.toString(16);
+    if (padLength === 0) {
+        padLength = Math.ceil(hex.length / 2);
+    }
+    hex = hex.padStart(padLength * 2, '0');
+    const length = hex.length / 2;
+    const arr = new Uint8Array(length);
+    for (let i = 0; i < length; i++) {
+        arr[i] = parseInt(hex.slice(i * 2, i * 2 + 2), 16);
+    }
+    return arr;
+}
+
+export function u8ArrayToBigInt(arr) {
+    let hex = '0x';
+    for (let i = 0; i < arr.length; i++) {
+        hex += arr[i].toString(16).padStart(2, '0');
+    }
+    return BigInt(hex);
+}