man SMIME_write_PKCS7 () - convert PKCS#7 structure to S/MIME format.
NAME
SMIME_write_PKCS7 - convert PKCS#7 structure to S/MIME format.
SYNOPSIS
int SMIME_write_PKCS7(BIO *out, PKCS7 *p7, BIO *data, int flags);
DESCRIPTION
SMIME_write_PKCS7() adds the appropriate MIME headers to a PKCS#7 structure to produce an S/MIME message.
out is the BIO to write the data to. p7 is the appropriate PKCS7 structure. If cleartext signing (multipart/signed) is being used then the signed data must be supplied in the data argument. flags is an optional set of flags.
NOTES
The following flags can be passed in the flags parameter.
If PKCS7_DETACHED is set then cleartext signing will be used, this option only makes sense for signedData where PKCS7_DETACHED is also set when PKCS7_sign() is also called.
If the PKCS7_TEXT flag is set MIME headers for type text/plain are added to the content, this only makes sense if PKCS7_DETACHED is also set.
If the PKCS7_PARTSIGN flag is set the signed data is finalized and output along with the content. This flag should only be set if PKCS7_DETACHED is also set and the previous call to PKCS7_sign() also set these flags.
If cleartext signing is being used and PKCS7_PARTSIGN not set then the data must be read twice: once to compute the signature in PKCS7_sign() and once to output the S/MIME message.
BUGS
SMIME_write_PKCS7() always base64 encodes PKCS#7 structures, there should be an option to disable this.
RETURN VALUES
SMIME_write_PKCS7() returns 1 for success or 0 for failure.
SEE ALSO
ERR_get_error(3), PKCS7_sign(3), PKCS7_verify(3), PKCS7_encrypt(3) PKCS7_decrypt(3)
HISTORY
SMIME_write_PKCS7() was added to OpenSSL 0.9.5