In identity-based encryption (IBE) the public key of a user $A$ is some identity string $ID_A$, e.g., an email address. To encrypt a message for this user there is no need to retrieve an authentic copy of the public key, as it is in public key cryptography, but one can simply use the identity string ...

learn more… | top users | synonyms

0
votes
1answer
27 views

Cocks IBE Scheme: why is -a a quadratic residue mod n?

In the Cocks IBE scheme it is required for the hash function, that the Jacobi symbol of its output and the universally available moduls $n = p*q$ is $+1$, so: $\Big(\frac{H(ID)}{n}\Big) = ...
1
vote
1answer
30 views

Question about Delerablée's Identity-based Broadcast Encryption

I'm reading “Identity-Based Broadcast Encryption with Constant Size Ciphertexts and Private Keys” by Cécile Delerablée. In Page 207, encryption process needs $\gamma$ which is part of master key. ...
4
votes
1answer
98 views

Generic group model: use of polynomials in the proof of the master theorem

I've been looking at the paper of Boneh, Boyen, Goh Hierarchical Identity Based Encryption with Constant Size Ciphertext which contains a general theorem (Theorem A.2) about the advantage of an ...
0
votes
0answers
35 views

Is Attribute based encryption sub-class of Identity based encryption [duplicate]

I have a basic question related to Identity and Attribute based encryption. Construction of IBE scheme was first shown by Boneh et al. in 2001 and I think in 2004 Sahai and Waters introduced ...
1
vote
2answers
101 views

What is “msg = group.random(GT)” in Charm encryption schemes?

In many encryption schemes in Charm the random group message is used instead of a text-message: msg = group.random(GT) For example, in CP-ABE scheme, random ...
0
votes
1answer
98 views

what is the difference between IBE and ABE schemes

Can somebody explain in simple words. real life example light help and limitations of these schemes etc.
1
vote
1answer
133 views

Is it feasible to use combination of ABE schemes for encrypting the data?

I have a peculiar requirement for preserving the shared log files. For example I have 1000 records which belong to different organizations as listed below and all the logs are present in a single CSV ...
2
votes
1answer
61 views

Question on Waters IBE

I'm reading “Efficient Identity-Based Encryption Without Random Oracles” by Brent Waters. In Page 9, I don't know how ...
5
votes
1answer
1k views

What is Attribute Based Encryption?

Can someone explain what attribute based encryption is? I was searching for a book or something that can help me in this regard but so far I have found none. Google also returns practically nothing ...
4
votes
3answers
192 views

How to prove identity without revealing identity

Let us say Alice publishes a book under the name of Claire. The book becomes wildly popular and now Bob comes along, claiming to be Claire, to reap all the success. How does Alice prove that she wrote ...
5
votes
1answer
146 views

What is the “artificial abort” technique?

In the security proof of Brent Waters's paper Efficient Identity-Based Encryption Without Random Oracles, he uses a novel “artificial abort” step on page 6. At this point the simulator is still ...
1
vote
1answer
91 views

Question about dual system encryption

Recently, I have been reading some dual system encryption papers. In these systems, is the adversary able to generate “semi-functional ciphertexts”?
2
votes
1answer
92 views

Pairings in Identity-based encryption vs. Attribute-based encryption

The bilinear map in Identity-based encryption should satisfy $e(aP,bQ)=e(P,Q)^{a\cdot b}$ whereas Attribute-based encryption schemes use $e(P^a,Q^a)=e(P,Q)^{a\cdot b}$ with $a,b\in\mathbb{Z}_p$ and ...
1
vote
0answers
80 views

How to compare different signature scheme's performance?

I am interested in comparing the computational performance of two signature schemes. However, I am unsure how to do that. My candidates are RSA and Shamir's ID Based Signature scheme. To get a fair ...
1
vote
2answers
77 views

Shamir's ID based signatures - Notation issues

I am currently implementing Shamir's ID Based signature scheme as defined in the original paper. The sign and verify operation are defined as follows: Sign: $s = g * r^{f(t,m)} (\mod n)$ ...
1
vote
2answers
248 views

Shamir's ID based signatures

I am currently implementing Shamir's ID based signature algorithm as proposed in Adi Shamir, Identity-Based Cryptosystems and Signature Schemes. Advances in Cryptology: Proceedings of CRYPTO 84, ...
2
votes
1answer
201 views

what's the advantages of identity-based systems over certificate-based ones?

Actually, I'm not familiar to how identity-based and certificate-based systems work, so ,can anyone give me a detail and comprehensive answer to this question? Moreover, in what environments the ...
1
vote
0answers
92 views

Could MITM securely identify identity?

Consider protocol like QUIC or MinimaLT which are essentially layer4 replacement for TCP/UDP (riding on top of UDP currently because of fear of random firewalls dropping new L4 protocol). From crypto ...
2
votes
0answers
215 views

How does identification currently work with the German identity card? [closed]

Since 18th of December 2010 Germany makes use of an identity card that should allow electronic authentication: (image source: commons.wikipedia.org) From a users perspective, the authentication ...
2
votes
1answer
149 views

a possibly stronger type of attack on identity-based encryption

What is known about the security of identity-based encryption schemes against attacks that involve seeing multiple ciphertexts and then receiving the private keys corresponding to some of those ...
4
votes
3answers
309 views

What crypto system allows for 3 parties: Party 1 who makes an assertion, Party 2 mutates the assertion, Party 3 validates it

I'm looking for the cryptographic equivalent of a Drivers license where the issuer can be verified, the issuer doesn't need to know who you showed the drivers license to, but also allows ...
4
votes
3answers
620 views

Is there any semantic difference between predicate encryption and functional encryption?

Predicate encryption(PE) arrived as a descendant of attribute based encryption. Attribute based encryption allows the encryptor to embody a policy to the ciphertext (Ciphertext-Policy based ...