Questions tagged [identity-based-encryption]
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 $ID_A$.
114 questions
3 votes
1 answer
162 views
Which Variant of the Decisional Bilinear DH Assumption is Stronger?
The following definitions are from Fuzzy Identity-based Encryption by Sahai and Waters (Eurocrypt 2005, Eprint). Definition 2 (Decisional Bilinear Diffie-Hellman (BDH) Assumption). Suppose a ...
- 33
2 votes
0 answers
75 views
Why are OO-secure ID-schemes IMP-PA?
Consider the paper From Identification to Signatures via the Fiat-Shamir Transform: Minimizing Assumptions for Security and Forward-Security published by Abdalla, An, Bellare, Namprempre. In their ...
- 101
1 vote
0 answers
74 views
secure channel for sending partial private keys!
In certificateless cryptography, the KGC must ensure that the partial private keys are delivered securely to the correct entities. So my question is how KGC can send these keys secretly? In the other ...
- 31
2 votes
1 answer
91 views
Question about Security proof of Gentry's Anonymous IBE
In Gentry's paper "Practical Identity-Based Encryption without Random Oracles", I have a little difficulty understanding the security proof part. The paper claims that in the Challenge phase:...
- 21
3 votes
1 answer
85 views
self-decryption paradox in identity based encryption
In the paper Dual system encryption: realizing fully secure IBE and HIBE under simple assumption (free PDF), the authors said "there is an apparent paradox in this strategy since it seems that ...
- 351
0 votes
1 answer
124 views
Well-known public key with non-interactive deniable encryption
Alice wants to send Bob a message. Both have well known public/private EC keys (PA, b, PB, <...
- 470
4 votes
1 answer
181 views
"Shifting" a dual-Regev keypair away from a trapdoored instance
This question pertains to identity-based key encapsulation mechanisms (IB-KEMs). To recap the functionality: $\mathsf{KeyGen}(1^\lambda) \to (\mathsf{msk}, \mathsf{mpk})$ Generates the master keypair ...
- 570
1 vote
1 answer
67 views
OTP like Identity
I am a developer with very little experience on the crypto part, and I'm looking for a secure solution (OTP Like) for identifying between client (browser) and server. this is what i need: Web Page at ...
1 vote
1 answer
145 views
Why use pairing to construct identity based encryption?
Identity Based Encryption is an asymmetric encryption scheme such that encryption uses the receiver's identity as the public key. Such a identity can be receiver's email address or some other string ...
- 75
2 votes
1 answer
582 views
Properties of the bilinear pairing groups?
I stumbled across this correctness of a scheme: $e(g^r, H(id)^x) = e(g^x, H(id))^r = e(g^x, H(id))^r$ and have a hard time following the properties of the bilinear pairing. Does anyone know the "...
- 353
0 votes
1 answer
54 views
Distributing the Master Public Key in Identity-based Encryption systems
I was just wondering how the private key generator should publish the master public key inside of an IBE system. This key is needed for all devices in the network to derive the public key of receiving ...
1 vote
3 answers
215 views
Proving identity in asymmetrically encrypted communication
Let's assume such a scenario. Person A will broadcast his public key and person B will broadcast his public key. They can now communicate. But let's say that suddenly another person C will write to ...
- 111
2 votes
2 answers
247 views
Is this RSA-based IBE Scheme secure?
The PKG performs the following steps Choose $p,q \in \mathbb{P}$. Calculate $N=pq$. Calculate $\phi (n)=(p-1)(q-1)$. Choose $e$ with $gcd(e,\phi(n))=1$ and $1 < e < \phi(n)$. Let it be $e = {p^{...
- 53
0 votes
1 answer
77 views
Why has ID-based PKC not been included in the NIST PQC competition?
Although there are several proposals of ID-based PKC based on lattices, multivariate cryptography, I want to know why identity (ID) based PKC is not included in the NIST post-quantum competition. Is ...
- 215
1 vote
0 answers
38 views
Is there a robust Identity-Based Digital Signature algorithm?
I'm looking for a IB-DS algorithm in the web. I found this one (if you know some other let me know). But I cannot figure out what the "identity" is. Better: I don't know if, in the section ...
- 167