5 PKCS7_encrypt - create a PKCS#7 envelopedData structure
9 #include <openssl/pkcs7.h>
11 PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher,
16 PKCS7_encrypt() creates and returns a PKCS#7 envelopedData structure. B<certs>
17 is a list of recipient certificates. B<in> is the content to be encrypted.
18 B<cipher> is the symmetric cipher to use. B<flags> is an optional set of flags.
22 Only RSA keys are supported in PKCS#7 and envelopedData so the recipient
23 certificates supplied to this function must all contain RSA public keys, though
24 they do not have to be signed using the RSA algorithm.
26 EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use
27 because most clients will support it.
29 Some old "export grade" clients may only support weak encryption using 40 or 64
30 bit RC2. These can be used by passing EVP_rc2_40_cbc() and EVP_rc2_64_cbc()
33 The algorithm passed in the B<cipher> parameter must support ASN1 encoding of
36 Many browsers implement a "sign and encrypt" option which is simply an S/MIME
37 envelopedData containing an S/MIME signed message. This can be readily produced
38 by storing the S/MIME signed message in a memory BIO and passing it to
41 The following flags can be passed in the B<flags> parameter.
43 If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are
44 prepended to the data.
46 Normally the supplied content is translated into MIME canonical format (as
47 required by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation
48 occurs. This option should be used if the supplied data is in binary format
49 otherwise the translation will corrupt it. If B<PKCS7_BINARY> is set then
50 B<PKCS7_TEXT> is ignored.
52 If the B<PKCS7_STREAM> flag is set a partial B<PKCS7> structure is output
53 suitable for streaming I/O: no data is read from the BIO B<in>.
57 If the flag B<PKCS7_STREAM> is set the returned B<PKCS7> structure is B<not>
58 complete and outputting its contents via a function that does not
59 properly finalize the B<PKCS7> structure will give unpredictable
62 Several functions including SMIME_write_PKCS7(), i2d_PKCS7_bio_stream(),
63 PEM_write_bio_PKCS7_stream() finalize the structure. Alternatively finalization
64 can be performed by obtaining the streaming ASN1 B<BIO> directly using
69 PKCS7_encrypt() returns either a PKCS7 structure or NULL if an error occurred.
70 The error can be obtained from ERR_get_error(3).
74 L<ERR_get_error(3)>, L<PKCS7_decrypt(3)>
78 The B<PKCS7_STREAM> flag was added in OpenSSL 1.0.0.
82 Copyright 2002-2016 The OpenSSL Project Authors. All Rights Reserved.
84 Licensed under the OpenSSL license (the "License"). You may not use
85 this file except in compliance with the License. You can obtain a copy
86 in the file LICENSE in the source distribution or at
87 L<https://www.openssl.org/source/license.html>.