PKCS7_encrypt(3) OpenSSL PKCS7_encrypt(3)
PKCS7_encrypt - create a PKCS#7 envelopedData structure
PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER
*cipher, int flags);
PKCS7_encrypt() creates and returns a PKCS#7 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 flags.
Only RSA keys are supported in PKCS#7 and envelopedData so the recipi-
ent 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.
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
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 PKCS7_encrypt().
The following flags can be passed in the flags parameter.
If the PKCS7_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 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
PKCS7_BINARY is set then PKCS7_TEXT is ignored.
PKCS7_encrypt() returns either a valid PKCS7 structure or NULL if an
error occurred. The error can be obtained from ERR_get_error(3).
The lack of single pass processing and need to hold all data in memory
as mentioned in PKCS7_sign() also applies to PKCS7_verify().
PKCS7_decrypt() was added to OpenSSL 0.9.5
3rd Berkeley Distribution 0.9.7d PKCS7_encrypt(3)