Hello, I’ve been asked to support an optional feature when using S/MIME signed message transmission for (as they call it) „Algorithm identifier protection“, which is defined in RFC6211. As I’ve found no evidence in the headers of openSSL, I’m asking you if this feature is available or planned. Actually, I’m using the latest openSSL version 1.1.1 with funtions for PKCS7 signing (PKCS7_sign, PKCS7_sign_add_signer, SMIME_write_PKCS7). Regards, Harald Koch