1=pod 2 3=head1 NAME 4 5PKCS7_encrypt - create a PKCS#7 envelopedData structure 6 7=head1 SYNOPSIS 8 9 #include <openssl/pkcs7.h> 10 11 PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags); 12 13=head1 DESCRIPTION 14 15PKCS7_encrypt() creates and returns a PKCS#7 envelopedData structure. B<certs> 16is a list of recipient certificates. B<in> is the content to be encrypted. 17B<cipher> is the symmetric cipher to use. B<flags> is an optional set of flags. 18 19=head1 NOTES 20 21Only RSA keys are supported in PKCS#7 and envelopedData so the recipient certificates 22supplied to this function must all contain RSA public keys, though they do not have to 23be signed using the RSA algorithm. 24 25EVP_des_ede3_cbc() (triple DES) is the algorithm of choice for S/MIME use because 26most clients will support it. 27 28Some old "export grade" clients may only support weak encryption using 40 or 64 bit 29RC2. These can be used by passing EVP_rc2_40_cbc() and EVP_rc2_64_cbc() respectively. 30 31The algorithm passed in the B<cipher> parameter must support ASN1 encoding of its 32parameters. 33 34Many browsers implement a "sign and encrypt" option which is simply an S/MIME 35envelopedData containing an S/MIME signed message. This can be readily produced 36by storing the S/MIME signed message in a memory BIO and passing it to 37PKCS7_encrypt(). 38 39The following flags can be passed in the B<flags> parameter. 40 41If the B<PKCS7_TEXT> flag is set MIME headers for type B<text/plain> are prepended 42to the data. 43 44Normally the supplied content is translated into MIME canonical format (as required 45by the S/MIME specifications) if B<PKCS7_BINARY> is set no translation occurs. This 46option should be used if the supplied data is in binary format otherwise the translation 47will corrupt it. If B<PKCS7_BINARY> is set then B<PKCS7_TEXT> is ignored. 48 49=head1 RETURN VALUES 50 51PKCS7_encrypt() returns either a valid PKCS7 structure or NULL if an error occurred. 52The error can be obtained from ERR_get_error(3). 53 54=head1 BUGS 55 56The lack of single pass processing and need to hold all data in memory as 57mentioned in PKCS7_sign() also applies to PKCS7_verify(). 58 59=head1 SEE ALSO 60 61L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_decrypt(3)|PKCS7_decrypt(3)> 62 63=head1 HISTORY 64 65PKCS7_decrypt() was added to OpenSSL 0.9.5 66 67=cut 68