I'm trying trying to implement exchange of CMS encrypted content using the pkijs library. Basically I've just copied the example from here: https://pkijs.org/examples/CMSEnvelopedExample.html

here the excerpt for encryption

cmsEnveloped.addRecipientByCertificate(certSimpl, {  oaepHashAlgorithm: oaepHashAlg });

return cmsEnveloped.encrypt(encAlg, valueBuffer).then(() => {
  var cmsContentSimpl = new ContentInfo();
  cmsContentSimpl.contentType = "1.2.840.113549.1.7.3";
  cmsContentSimpl.content = cmsEnveloped.toSchema();
  cmsEnvelopedBuffer = cmsContentSimpl.toSchema().toBER(false);

The problematic part is the binary encoding of the asn.1 schema with .toBER(false). If the valueBuffer is not extremely small it is very slow ~13sek for 1 Mb. My question are: why is this so slow? and could I just encode it differently e.g. toJSON()and then stringToArrayBuffer? Are there any security concerns?