Dear Mithun, I came across this thread by researching the same question: > > Does openssl support "S/MIME Capabilities" certificate extension?
For the following shortened code: /* display the cert extension list here */ for (i=0; i<sk_X509_EXTENSION_num(ext_list); i++) { ASN1_OBJECT *obj; X509_EXTENSION *ext; ext = sk_X509_EXTENSION_value(ext_list, i); obj = X509_EXTENSION_get_object(ext); // ommitting a few fprintf lines of output formatting i2a_ASN1_OBJECT(outbio, obj); // ommitting a few fprintf lines of output formatting if (!X509V3_EXT_print(outbio, ext, 0, 0)) { /* Some extensions (i.e. LogoType) have no handling * * defined, we need to print their content as hex data */ fprintf(cgiOut, "%*s", 0, ""); M_ASN1_OCTET_STRING_print(outbio, ext->value); } ...used with a CSR having that extension set, I get this output: S/MIME Capabilities 050...*.H.. ......0...*.H.. ......0...+....0 ..*.H.. .. It seems that X509V3_EXT_print() fails to decode, and M_ASN1_OCTET_STRING_print() kicks in to show the raw content. OpenSSL knows about the "S/MIME Capabilities" OID (1.2.840.113549.1.9.15 per RFC4262), but it seems there is no handling for the ASN.1 sequence underneath. There is a related <a href="http://www.mail-archive.com/openssl- us...@openssl.org/msg58514.html">old thread</a> from 2009 with the recipe for manually adding the SMIME Capabilities to openssl.cnf. I hope this helps! Frank ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org