encryption
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... the MIME multipart content type: signed and encrypted. In each of
the security subtypes, there are exactly two related body parts: one
...
... and contents of the control information body parts are determined by
the value of the protocol parameter of the enclosing multipart/signed
or multipart/encrypted content type, which is required to be present.
By registering new values for the required protocol parameter, the
...
... content type specifies how to support
confidentiality via encryption. The control information is carried
in the first of the two required body parts.
...
...
A three-step process is described for the origination and reception
of the multipart/signed and multipart/encrypted contents. The
details of the processing performed during each step is left to be
specified by the security protocol ...
... Definition of Multipart/Encrypted ...
... MIME subtype name: encrypted
...
...
The multipart/encrypted content type contains exactly two body parts.
The first body part contains the control information necessary to
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... decrypt the data in the second body part and is labeled according to
the value of the protocol parameter. The second body part contains
the data which was encrypted and is always labeled
application/octet-stream.
...
...
When creating a multipart/encrypted body part, the following sequence
of steps describes the processing necessary. It must be emphasized
that these steps are descriptive, not prescriptive, and in no way
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... The body part (headers and content) to be encrypted is prepared for
encryption according to the value of the protocol parameter. The
...
... headers and content) to be encrypted is prepared for
encryption according to the value of the protocol parameter. The
MIME headers of the encrypted ...
... encryption according to the value of the protocol parameter. The
MIME headers of the encrypted body part are included in the
encryption to protect from disclosure the MIME ...
... MIME headers of the encrypted body part are included in the
encryption to protect from disclosure the MIME labeling of the
data that is encrypted ...
... The prepared body part is made available to the encryption process
according to a local convention. The encryption process must make
...
... The prepared body part is made available to the encryption process
according to a local convention. The encryption process must make
available to a MIME implementation two data streams ...
... implementation will place in the first body part and label
according to the value of the protocol parameter, and the
encrypted body part, which the MIME implementation will place in
the second body part and label application/octet-stream ...
... the second body part and label application/octet-stream. Thus,
when used in a multipart/encrypted, the application/octet-stream
data is comprised of a nested MIME ...
...
When receiving a multipart/encrypted body part, the following
sequence of steps describes the processing necessary to decrypt the
enclosed data. It must be emphasized that these steps are
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... MIME implementation the result of the
decryption and the decrypted form of the encrypted body part.
...
... MIME implementation will not be able to display the
received form of the second body part because the
application of encryption will transform the body part.
This transformation will not be described in the MIME
headers (Content-Type ...
... rather, will be described in the content of the first body
part. Therefore, an implementation should wait until the
encryption has been removed before attempting to display
the content.
...
...
The following example is an illustration of a multipart/encrypted
body part. It is necessarily incomplete since the control
information is defined by the security protocol ...
... Content-Type: multipart/encrypted; protocol="TYPE/STYPE";
boundary="Encrypted Boundary"
--Encrypted ...
... CONTROL INFORMATION for protocol "TYPE/STYPE" would be here
--Encrypted Boundary
Content-Type: application/octet-stream ...
... All of this indented text, including the indented headers,
would be unreadable since it would have been encrypted by
the protocol "TYPE/STYPE". Also, this encrypted data could
...
... would be unreadable since it would have been encrypted by
the protocol "TYPE/STYPE". Also, this encrypted data could
be any type of data, labeled accordingly, of course.
...
... be any type of data, labeled accordingly, of course.
--Encrypted Boundary--
...
... MIME body parts. A minimal MIME implementation will be
able to recognize multipart/signed and multipart/encrypted body parts
and be able to identify the protected data and control information
body parts within them.
...
... This specification describes an enhancement to MIME to support signed
and encrypted body parts. In that context this entire document is
about security ...