diff --git a/lib/help/asn1/index.js b/lib/help/asn1/index.js
index ff7e357c9e..1684c6bb55 100644
--- a/lib/help/asn1/index.js
+++ b/lib/help/asn1/index.js
@@ -27,3 +27,4 @@ const RSAPublicKey = asn1.define('RSAPublicKey', require('./rsa_public_key'))
 types.set('RSAPublicKey', RSAPublicKey)
 
 module.exports = types
+module.exports.bignum = asn1.bignum
diff --git a/lib/help/key_utils.js b/lib/help/key_utils.js
index c3ff9a2397..b88c911dc0 100644
--- a/lib/help/key_utils.js
+++ b/lib/help/key_utils.js
@@ -8,6 +8,7 @@ const asn1 = require('./asn1')
 const computePrimes = require('./rsa_primes')
 const { OKP_CURVES, EC_CURVES } = require('./consts')
 
+const BN = asn1.bignum
 const oidHexToCurve = new Map([
   ['06082a8648ce3d030107', 'P-256'],
   ['06052b8104000a', secp256k1],
@@ -212,14 +213,14 @@ const jwkToPem = {
 
       return RSAPrivateKey.encode({
         version: 0,
-        n: base64url.decodeToBuffer(jwk.n),
-        e: base64url.decodeToBuffer(jwk.e),
-        d: base64url.decodeToBuffer(jwk.d),
-        p: base64url.decodeToBuffer(jwk.p),
-        q: base64url.decodeToBuffer(jwk.q),
-        dp: base64url.decodeToBuffer(jwk.dp),
-        dq: base64url.decodeToBuffer(jwk.dq),
-        qi: base64url.decodeToBuffer(jwk.qi)
+        n: new BN(base64url.decodeToBuffer(jwk.n)),
+        e: new BN(base64url.decodeToBuffer(jwk.e)),
+        d: new BN(base64url.decodeToBuffer(jwk.d)),
+        p: new BN(base64url.decodeToBuffer(jwk.p)),
+        q: new BN(base64url.decodeToBuffer(jwk.q)),
+        dp: new BN(base64url.decodeToBuffer(jwk.dp)),
+        dq: new BN(base64url.decodeToBuffer(jwk.dq)),
+        qi: new BN(base64url.decodeToBuffer(jwk.qi))
       }, 'pem', { label: 'RSA PRIVATE KEY' })
     },
     public (jwk) {
@@ -227,8 +228,8 @@ const jwkToPem = {
 
       return RSAPublicKey.encode({
         version: 0,
-        n: base64url.decodeToBuffer(jwk.n),
-        e: base64url.decodeToBuffer(jwk.e)
+        n: new BN(base64url.decodeToBuffer(jwk.n)),
+        e: new BN(base64url.decodeToBuffer(jwk.e))
       }, 'pem', { label: 'RSA PUBLIC KEY' })
     }
   },