diff --git a/src/signature.derive.ts b/src/signature.derive.ts
index dd3820c..a5f01c7 100644
--- a/src/signature.derive.ts
+++ b/src/signature.derive.ts
@@ -65,7 +65,7 @@ function crypto_pubkey(point: ProjPointType<bigint>) : Promise<CryptoKey> {
     )
 }
 function bg2b64url(n: bigint) : string {
-    return encode(btoa(String.fromCharCode(0) + String.fromCharCode(...hexToBytes(numberToHexUnpadded(n)))))
+    return encode(btoa(String.fromCharCode(...hexToBytes(numberToHexUnpadded(n)))))
 }
 function encode(input: string) : string {
     // Replace non-url compatible chars with base64 standard chars