trademark

7.0 Cryptographic Technologies for Big Data (cont.)
members want to cooperate, while ring signatures are useful when the members do not
want to cooperate. Both group signatures and ring signatures are signer-ambiguous, but
in a ring signature scheme there are no pre-arranged groups of users; no procedures for
setting, changing, or deleting groups; no way to distribute specialized keys; and no way to
revoke the anonymity of the actual signer. The only assumption is that each member is
already associated with the public key of some standard signature scheme. To produce a
ring signature, the actual signer declares an arbitrary set of possible signers that includes
himself, and computes the signature entirely by himself using only his secret key and the
others public keys.
7.6 Implement identity-based encryption
7.6.1 Why?
To overcome difficulties associated with key management of a public-key crypto
system. One of the major difficulties when practically deploying a system that relies on
public-key cryptography is the management of keys, including provisioning, updates,
and revocation. For instance, all communicating nodes must be equipped with
digital certificates issued by trusted certification authorities. Moreover, sufficient key
management is not feasible in a setting like the Internet of hings (IoT), where a large
number of resource-constrained devices are involved.
7.6.2 How?
In identity-based systems [Sha85] (IBE), plaintext can be encrypted for a given identity
and the expectation is that only an entity with that identity can decrypt the ciphertext.
Any other entity will be unable to decipher the plaintext, even with collusion. Boneh
and Franklin [BF01] came up with the first IBE using pairing-friendly elliptic curves.
Since then, there have been numerous efficiency and security improvements [Wat09,
CW13, JR13].
7.7 Utilize attribute-based encryption and
access control
7.7.1 Why?
To integrate access control and encryption in a practical manner. Traditionally, access
control to data has been enforced by systems—including operating systems and virtual
machines—which restrict access to data, based on some access policy. The data is still
in plaintext. There are at least two problems to the systems’ paradigm: (1) systems can
be hacked; and (2) security of the same data in transit is a separate concern.
CLOUD SECURITY ALLIANCE Big Data Working Group Guidance
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