<p>Suppose we have an <a href="http://en.wikipedia.org/wiki/ID-based_encryption" rel="nofollow">ID-based encryption (IBE)</a> (Setup, Extract, Enc, Dec) scheme which is <a href="http://en.wikipedia.org/wiki/Ciphertext_indistinguishability#Indistinguishability_under_chosen-plaintext_attack_.28IND-CPA.29" rel="nofollow">IND-ID-CPA</a> (resp <a href="http://en.wikipedia.org/wiki/Ciphertext_indistinguishability#Indistinguishability_under_chosen_ciphertext_attack.2Fadaptive_chosen_ciphertext_attack_.28IND-CCA.2C_IND-CCA2.29" rel="nofollow">IND-ID-CCA</a>) secure, and we want to construct <a href="http://en.wikipedia.org/wiki/Threshold_cryptosystem" rel="nofollow">threshold version</a> of this scheme.
My question is: how to define the IND-ID-XXX security game for the new scheme.</p>

CC BY-SA 3.0
2011-09-29T12:51:17.233Z
Please note that not all people here are experts in cryptography, while many are willing to help. If you describe the jargon or provide the links, you probably get an answer much faster. I added some links, but you'd better add some descriptions as well.
Sadeq Dousti
CC BY-SA 3.0
2011-09-29T12:55:37.973Z
And, by the way, have you seen this http://www.iacr.org/archive/pkc2004/29470260/29470260.pdf?
Sadeq Dousti
CC BY-SA 3.0
2011-10-12T03:39:07.420Z
Why would the situation be fundamentally different from the case of standard threshold encryption?
user6584
<cr.crypto-security>
Security of IBE schemes
sam
# Security of IBE schemes

(Asked by: username_0 on 2011-09-28)

Suppose we have an [ID-based encryption (IBE)](http://en.wikipedia.org/wiki/ID-based_encryption) (Setup, Extract, Enc, Dec) scheme which is [IND-ID-CPA](http://en.wikipedia.org/wiki/Ciphertext_indistinguishability#Indistinguishability_under_chosen-plaintext_attack_.28IND-CPA.29) (resp [IND-ID-CCA](http://en.wikipedia.org/wiki/Ciphertext_indistinguishability#Indistinguishability_under_chosen_ciphertext_attack.2Fadaptive_chosen_ciphertext_attack_.28IND-CCA.2C_IND-CCA2.29)) secure, and we want to construct [threshold version](http://en.wikipedia.org/wiki/Threshold_cryptosystem) of this scheme.
My question is: how to define the IND-ID-XXX security game for the new scheme.

**Tags:** cr.crypto-security
> **Comments:**
> **username_1**: Please note that not all people here are experts in cryptography, while many are willing to help. If you describe the jargon or provide the links, you probably get an answer much faster. I added some links, but you'd better add some descriptions as well.  
> **username_1**: And, by the way, have you seen this http://www.iacr.org/archive/pkc2004/29470260/29470260.pdf?  
> **username_2**: Why would the situation be fundamentally different from the case of standard threshold encryption?  

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## 0 answers

