=head1 NOTES
-Only RSA keys are supported in PKCS#7 and envelopedData so the recipient certificates
-supplied to this function must all contain RSA public keys, though they do not have to
-be signed using the RSA algorithm.
+Only RSA keys are supported in PKCS#7 and envelopedData so the recipient
+certificates supplied to this function must all contain RSA public keys, though
+they do not have to be signed using the RSA algorithm.
-EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use because
-most clients will support it.
+EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use
+because most clients will support it.
-Some old "export grade" clients may only support weak encryption using 40 or 64 bit
-RC2. These can be used by passing EVP_rc2_40_cbc() and EVP_rc2_64_cbc() respectively.
+Some old "export grade" clients may only support weak encryption using 40 or 64
+bit RC2. These can be used by passing EVP_rc2_40_cbc() and EVP_rc2_64_cbc()
+respectively.
-The algorithm passed in the B<cipher> parameter must support ASN1 encoding of its
-parameters.
+The algorithm passed in the B<cipher> parameter must support ASN1 encoding of
+its parameters.
-Many browsers implement a "sign and encrypt" option which is simply an S/MIME
+Many browsers implement a "sign and encrypt" option which is simply an S/MIME
envelopedData containing an S/MIME signed message. This can be readily produced
by storing the S/MIME signed message in a memory BIO and passing it to
PKCS7_encrypt().
The following flags can be passed in the B<flags> parameter.
-If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended
-to the data.
+If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are
+prepended to the data.
-Normally the supplied content is translated into MIME canonical format (as required
-by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation occurs. This
-option should be used if the supplied data is in binary format otherwise the translation
-will corrupt it. If B<PKCS7_BINARY> is set then B<PKCS7_TEXT> is ignored.
+Normally the supplied content is translated into MIME canonical format (as
+required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation
+occurs. This option should be used if the supplied data is in binary format
+otherwise the translation will corrupt it. If B<PKCS7_BINARY> is set then
+B<PKCS7_TEXT> is ignored.
-=head1 RETURN VALUES
+If the B<PKCS7_STREAM> flag is set a partial B<PKCS7> structure is output
+suitable for streaming I/O: no data is read from the BIO B<in>.
-PKCS7_encrypt() returns either a valid PKCS7 structure or NULL if an error occurred.
-The error can be obtained from ERR_get_error(3).
+=head1 NOTES
+
+If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not>
+complete and outputting its contents via a function that does not
+properly finalize the B<PKCS7> structure will give unpredictable
+results.
-=head1 BUGS
+Several functions including SMIME_write_PKCS7(), d2i_PKCS7_bio_stream(),
+PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization
+can be performed by obtaining the streaming ASN1 B<BIO> directly using
+BIO_new_PKCS7().
-The lack of single pass processing and need to hold all data in memory as
-mentioned in PKCS7_sign() also applies to PKCS7_verify().
+=head1 RETURN VALUES
+
+PKCS7_encrypt() returns either a PKCS7 structure or NULL if an error occurred.
+The error can be obtained from ERR_get_error(3).
=head1 SEE ALSO
=head1 HISTORY
PKCS7_decrypt() was added to OpenSSL 0.9.5
+The B<PKCS7_STREAM> flag was first supported in OpenSSL 0.9.9.
=cut
projects / openssl.git / blobdiff