How to give passphrase when adding certificate and key in Kong upstream service?

curl -i -X POST kong-ip:8001/certificates
-F “cert=@/home/xyz/Downloads/abc.pem”
-F “key=@/home/xyz/Downloads/abcdef.pem”
-F “snis=something.com

I tried the above cURL but it doesn’t work. The .pem key file has a passphrase, not sure how to give that.

Error:
schema violation (key: invalid key: pkey.new:load_key: asn1/tasn_dec.c:309:error:0D07803A:asn1 encoding routines:asn1_item_embed_d2i:nested asn1 error)

invalid key: pkey.new:load_key: asn1/tasn_dec.c:309:error:0D07803A:asn1 encoding routines:asn1_item_embed_d2i:nested asn1 error