In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. In this paper, with the help of the PKG, we construct a CCA-secure identity based proxy reencryption scheme based on a variant of BBi identity based encryption (IBE), we also prove its security in the random oracle model.
In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. In this paper, with the help of the PKG, we construct a CCA-secure identity based proxy reencryption scheme based on a variant of BBi identity based encryption (IBE), we also prove its security in the random oracle model.
In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. In this paper, we pay attention to the role of P KG for proxy re-encryption in identity based setting. We find that if we allow the PKG using its master-key in the process of generating re-encryption key for proxy re-encryption in identity based setting, it is easy to construct an identity based proxy re-encryption scheme based on a variant of BBi identity based encryption (IBE), we also prove its security in the standard model.
In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice’s public key into one that can be opened under Bob’s decryption key. In 2007, Matsuo proposed the concept of four types of proxy re-encryption schemes: CBE (Certificate Based Public Key Encryption) to IBE (Identity Based Encryption) (type 1), IBE to IBE (type 2), IBE to CBE (type 3), CBE to CBE (type 4). In this paper, we find that if we allow the PKG to use its masterkey in the process of generating re-encryption key for proxy re-encryption in identity based setting, many open problems can be solved. We give the new security models for proxy reencryption in identity based setting, especially considering PKG’s involving in the re-encryption key generation process and PKG’s master-key’s security. We construct the new IND-ID-CPA and the first IND-ID-CCA2 secure proxy reencryption schemes based on BB1 IBE. We also prove their security by introducing some new techniques which maybe have independent interest. At last, we compare our new schemes with existing ones, the results show that our scheme can achieve high security levels and are very efficient for re-encryption and, which are very important for practical applications.
In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. They predicated that proxy re-encryption and re-signature will play an important role in our life. In 2007, Matsuo proposed the concept of four types of re-encryption schemes: CBE to IBE(type 1), IBE to IBE(type 2), IBE to CBE (type 3), CBE to CBE (type 4 ). Now CBE to IBE and IBE to IBE proxy re-encryption schemes are being standardized by IEEEP1363.3 working group. One feature of proxy re-encryption schemes proposed by Matsuo is that they are all based on BB1 identity based encryption.We ask question like this: can we construct proxy re-encryption schemes based on BB2 identity based encryption? We give affirmative answer to this question. We construct an IBE to IBE proxy re-encryption scheme based on BB2 with the help of PKG and prove its security in the standard model.
The concept of proxy re-cryptography comes from the work of Blaze, Bleumer, and Strauss in 1998. The goal of proxy re-encryption is to securely enable the re-encryption of ciphertexts from one key to another, without relying on trusted parties. In 2007, Matsuo proposed the concept of four types of proxy re-encryption schemes: CBE to CBE, IBE to CBE, CBE to IBE and IBE to IBE. Now CBE to IBE and IBE to IBE proxy re-encryption schemes are being standardized by IEEEP1363.3 working group. One feature of their schemes is that they are all based on BB1 identity based encryption. We reconsider the problem of constructing proxy re-encryption based on SK identity based encryption. Surprisingly, if we consider the help of PKG, then it is easy to construct proxy re-encryption based on SK identity based encryption. Interestingly , our proxy re-encryption scheme even can achieve CCA2 secure, which makes it is unique.
Abstract. In 1998, Blaze, Bleumer, and Strauss proposed a kind of cryptographic primitive called proxy re-encryption[3]. In proxy re-encryption, a proxy can transform a ciphertext computed under Alice’s public key into one that can be opened under Bob’s decryption key. In 2007, Matsuo proposed the concept of four types of proxy re-encryption schemes: CBE(Certificate Based Public Key Encryption) to IBE(Identity Based Encryption)(type 1), IBE to IBE(type 2), IBE to CBE (type 3), CBE to CBE (type 4)[29]. Now CBE to IBE and IBE to IBE proxy re-encryption schemes are being standardized by IEEEP1363.3 working group[31]. In this paper, based on [29] we pay attention to the role of PKG for proxy re-encryption in identity based setting. We find that if we allow the PKG to use its master-key in the process of generating re-encryption key for proxy re-encryption in identity based setting, many open problems can be solved. Our main results are as following: We construct the first proxy re-encryption scheme from CBE to IBE which can resist malicious PKG attack, the first proxy re-encryption scheme from IBE to CBE, the second proxy re-encryption scheme based on a variant of BB1 IBE 1, the first proxy re-encryption scheme based on BB2 IBE, the first proxy re-encryption scheme based on SK IBE, we also prove their security in their corresponding security models. 1
Proxy re-encryption, introduced by Blaze et al. in 1998, allows a proxy to transform a ciphertext computed under Alice's public key into one that can be opened under Bob's decryption key. An open problem of constructing (bidirectional or unidirectional) IND-PRE-CCA2 secure proxy re-encryption scheme in the standard model yet without pairings was left until now. In this paper, based on Hanaoka's efficient chosen ciphertext secure public key encryption under the computational Diffie-Hellman assumption, we try to solve this open problem by presenting two new bidirectional proxy re-encryption schemes, which are restricted IND-PRE-CCA2 secure without pairing nor random oracle.