NAME
SMIME_write_PKCS7 —
convert PKCS#7 structure to S/MIME
format
SYNOPSIS
#include
<openssl/pkcs7.h>
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 streaming is enabled, then the content must be supplied in the data argument. flags is an optional set of flags.
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(3) 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_STREAM flag is set, streaming
is performed. This flag should only be set if
PKCS7_STREAM was also set in the previous call to
PKCS7_sign(3) or
PKCS7_encrypt(3).
The bit SMIME_OLDMIME is inverted before
passing on the flags to
SMIME_write_ASN1(3). Consequently, if this bit is set in the
flags argument, "application/pkcs7-mime" or
"application/pkcs7-signature" is used in Content-Type headers.
Otherwise, "application/x-pkcs7-mime" or
"application/x-pkcs7-signature" is used.
If cleartext signing is being used and
PKCS7_STREAM is not set, then the data must be read
twice: once to compute the signature in
PKCS7_sign(3) and once to output the S/MIME message.
If streaming is performed, the content is output in BER format using indefinite length constructed encoding except in the case of signed data with detached content where the content is absent and DER format is used.
RETURN VALUES
Upon successful completion, 1 is returned; otherwise 0 is returned and an error code can be retrieved with ERR_get_error(3).
SEE ALSO
i2d_PKCS7_bio_stream(3), PEM_write_bio_PKCS7_stream(3), PEM_write_PKCS7(3), PKCS7_final(3), PKCS7_new(3), SMIME_read_PKCS7(3), SMIME_write_ASN1(3)
HISTORY
SMIME_write_PKCS7() first appeared in
OpenSSL 0.9.5 and has been available since OpenBSD
2.7.
BUGS
SMIME_write_PKCS7() always base64 encodes
PKCS#7 structures. There should be an option to disable this.