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CMS_encrypt(3)                      OpenSSL                     CMS_encrypt(3)

       CMS_encrypt - create a CMS envelopedData structure

       libcrypto, -lcrypto

        #include <openssl/cms.h>

        CMS_ContentInfo *CMS_encrypt(STACK_OF(X509) *certs, BIO *in,
                                     const EVP_CIPHER *cipher, unsigned int flags);

       CMS_encrypt() creates and returns a CMS EnvelopedData structure. certs
       is a list of recipient certificates. in is the content to be encrypted.
       cipher is the symmetric cipher to use. flags is an optional set of

       Only certificates carrying RSA, Diffie-Hellman or EC keys are supported
       by this function.

       EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME
       use because most clients will support it.

       The algorithm passed in the cipher parameter must support ASN1 encoding
       of its parameters.

       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 CMS_encrypt().

       The following flags can be passed in the flags parameter.

       If the CMS_TEXT flag is set MIME headers for type 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 CMS_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
       CMS_BINARY is set then CMS_TEXT is ignored.

       OpenSSL will by default identify recipient certificates using issuer
       name and serial number. If CMS_USE_KEYID is set it will use the subject
       key identifier value instead. An error occurs if all recipient
       certificates do not have a subject key identifier extension.

       If the CMS_STREAM flag is set a partial CMS_ContentInfo structure is
       returned suitable for streaming I/O: no data is read from the BIO in.

       If the CMS_PARTIAL flag is set a partial CMS_ContentInfo structure is
       returned to which additional recipients and attributes can be added
       before finalization.

       The data being encrypted is included in the CMS_ContentInfo structure,
       unless CMS_DETACHED is set in which case it is omitted. This is rarely
       used in practice and is not supported by SMIME_write_CMS().

       If the flag CMS_STREAM is set the returned CMS_ContentInfo structure is
       not complete and outputting its contents via a function that does not
       properly finalize the CMS_ContentInfo structure will give unpredictable

       Several functions including SMIME_write_CMS(), i2d_CMS_bio_stream(),
       PEM_write_bio_CMS_stream() finalize the structure. Alternatively
       finalization can be performed by obtaining the streaming ASN1 BIO
       directly using BIO_new_CMS().

       The recipients specified in certs use a CMS KeyTransRecipientInfo info
       structure. KEKRecipientInfo is also supported using the flag
       CMS_PARTIAL and CMS_add0_recipient_key().

       The parameter certs may be NULL if CMS_PARTIAL is set and recipients
       added later using CMS_add1_recipient_cert() or

       CMS_encrypt() returns either a CMS_ContentInfo structure or NULL if an
       error occurred. The error can be obtained from ERR_get_error(3).

       ERR_get_error(3), CMS_decrypt(3)

       The CMS_STREAM flag was first supported in OpenSSL 1.0.0.

       Copyright 2008-2018 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use
       this file except in compliance with the License.  You can obtain a copy
       in the file LICENSE in the source distribution or at

1.1.1i                            2018-09-23                    CMS_encrypt(3)