PKCS7_sign_add_signer
if (!PKCS7_sign_add_signer(p7, signer, key, sign_md, flags))
if (pkey && !PKCS7_sign_add_signer(p7, signcert, pkey, NULL, flags)) {
if (!PKCS7_sign_add_signer(p7, scert, skey, NULL, 0))
if (!PKCS7_sign_add_signer(p7, scert2, skey2, NULL, 0))
PKCS7_SIGNER_INFO *PKCS7_sign_add_signer(PKCS7 *p7,
info = PKCS7_sign_add_signer(pkcs7, cert, key, md, 0);