Index: openssl/doc/crypto/CMS_encrypt.pod |
=================================================================== |
--- openssl/doc/crypto/CMS_encrypt.pod (revision 0) |
+++ openssl/doc/crypto/CMS_encrypt.pod (revision 0) |
@@ -0,0 +1,96 @@ |
+=pod |
+ |
+=head1 NAME |
+ |
+ CMS_encrypt - create a CMS envelopedData structure |
+ |
+=head1 SYNOPSIS |
+ |
+ #include <openssl/cms.h> |
+ |
+ CMS_ContentInfo *CMS_encrypt(STACK_OF(X509) *certs, BIO *in, const EVP_CIPHER *cipher, unsigned int flags); |
+ |
+=head1 DESCRIPTION |
+ |
+CMS_encrypt() creates and returns a CMS 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 certificates carrying RSA keys are supported 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. |
+ |
+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 |
+CMS_encrypt(). |
+ |
+The following flags can be passed in the B<flags> parameter. |
+ |
+If the B<CMS_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<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 B<CMS_BINARY> is set then |
+B<CMS_TEXT> is ignored. |
+ |
+OpenSSL will by default identify recipient certificates using issuer name |
+and serial number. If B<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 B<CMS_STREAM> flag is set a partial B<CMS_ContentInfo> structure is |
+returned suitable for streaming I/O: no data is read from the BIO B<in>. |
+ |
+If the B<CMS_PARTIAL> flag is set a partial B<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 |
+B<CMS_DETACHED> is set in which case it is omitted. This is rarely used in |
+practice and is not supported by SMIME_write_CMS(). |
+ |
+=head1 NOTES |
+ |
+If the flag B<CMS_STREAM> is set the returned B<CMS_ContentInfo> structure is |
+B<not> complete and outputting its contents via a function that does not |
+properly finalize the B<CMS_ContentInfo> structure will give unpredictable |
+results. |
+ |
+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 B<BIO> directly using |
+BIO_new_CMS(). |
+ |
+The recipients specified in B<certs> use a CMS KeyTransRecipientInfo info |
+structure. KEKRecipientInfo is also supported using the flag B<CMS_PARTIAL> |
+and CMS_add0_recipient_key(). |
+ |
+The parameter B<certs> may be NULL if B<CMS_PARTIAL> is set and recipients |
+added later using CMS_add1_recipient_cert() or CMS_add0_recipient_key(). |
+ |
+=head1 RETURN VALUES |
+ |
+CMS_encrypt() returns either a CMS_ContentInfo structure or NULL if an error |
+occurred. The error can be obtained from ERR_get_error(3). |
+ |
+=head1 SEE ALSO |
+ |
+L<ERR_get_error(3)|ERR_get_error(3)>, L<CMS_decrypt(3)|CMS_decrypt(3)> |
+ |
+=head1 HISTORY |
+ |
+CMS_decrypt() was added to OpenSSL 0.9.8 |
+The B<CMS_STREAM> flag was first supported in OpenSSL 1.0.0. |
+ |
+=cut |