On Fri, May 22, 2020 at 04:31:02PM -0500, Kyle Hamilton wrote: > application/pkix-pkipath > Defined in RFC4366 (section 8) and RFC6066 (section 10.1) > > PkiPath ::= SEQUENCE OF Certificate > > Within the sequence, the order of certificates is such that the subject of > the first certificate is the issuer of the second certificate, etc. One can also use PKCS#7 (Microsft uses the .SPC file extension): $ openssl crl2pkcs7 -nocrl -certfile certs.pem -outform DER That's perhaps more likely to be what the OP wants, if indeed he wants a commonly used DER-form multi-cert (no keys) object: https://www.file-extensions.org/spc-file-extension-pkcs-7-certificate -- Viktor.