| =pod |
| |
| =head1 NAME |
| |
| PKCS7_encrypt - create a PKCS#7 envelopedData structure |
| |
| =head1 SYNOPSIS |
| |
| PKCS7 *PKCS7_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, int flags); |
| |
| =head1 DESCRIPTION |
| |
| PKCS7_encrypt() creates and returns a PKCS#7 envelopedData structure. B<certs> |
| is a list of recipient certificates. B<in> is the content to be encrypted. |
| B<cipher> is the symmetric cipher to use. B<flags> is an optional set of flags. |
| |
| =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. |
| |
| 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. |
| |
| 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 |
| 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. |
| |
| 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 |
| |
| 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 BUGS |
| |
| 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 SEE ALSO |
| |
| L<ERR_get_error(3)|ERR_get_error(3)>, L<PKCS7_decrypt(3)|PKCS7_decrypt(3)> |
| |
| =head1 HISTORY |
| |
| PKCS7_decrypt() was added to OpenSSL 0.9.5 |
| |
| =cut |
