diff options
author | marha <marha@users.sourceforge.net> | 2010-03-30 12:36:28 +0000 |
---|---|---|
committer | marha <marha@users.sourceforge.net> | 2010-03-30 12:36:28 +0000 |
commit | ff48c0d9098080b51ea12710029135916d117806 (patch) | |
tree | 96e6af9caf170ba21a1027b24e306a07e27d7b75 /openssl/doc/crypto/CMS_encrypt.pod | |
parent | bb731f5ac92655c4860a41fa818a7a63005f8369 (diff) | |
download | vcxsrv-ff48c0d9098080b51ea12710029135916d117806.tar.gz vcxsrv-ff48c0d9098080b51ea12710029135916d117806.tar.bz2 vcxsrv-ff48c0d9098080b51ea12710029135916d117806.zip |
svn merge -r514:HEAD ^/branches/released .
Diffstat (limited to 'openssl/doc/crypto/CMS_encrypt.pod')
-rw-r--r-- | openssl/doc/crypto/CMS_encrypt.pod | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/openssl/doc/crypto/CMS_encrypt.pod b/openssl/doc/crypto/CMS_encrypt.pod new file mode 100644 index 000000000..1ee5b275e --- /dev/null +++ b/openssl/doc/crypto/CMS_encrypt.pod @@ -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 |