Maintaining data confidentiality at the asymmetric-resource devices across emerging technologies needs varying cryptographic algorithms. Quantum computing makes preserving data confidentiality across asymmetric infrastructure more difficult. However, exploiting the architecture of classical cryptographic schemes to integrate the post-quantum constructs could be used to maintain post-quantum level confidentiality over the Internet. This paper presents a post-quantum secure classical ABE-IBE proxy re-encryption scheme (L ABE-IBE PRE) that utilizes the classical ABE-IBE proxy re-encryption capabilities at the end nodes in a system and raises the data confidentiality to post-quantum secure level over the Internet. The proposed L ABE-IBE PRE transforms a ciphertext of the classical ABE scheme to a post-quantum secure ciphertext and from a post-quantum secure ciphertext to a ciphertext of the classical IBE scheme. We compare our proposed L ABE-IBE PRE scheme with classical ABE-IBE proxy re-encryption schemes, including Encryption Switching ABE-IBE (ES.ABE-IBE) scheme (He et al., 2019). We discuss the security and efficiency of our proposed scheme.
Maintaining data confidentiality at the asymmetric-resource devices across emerging technologies needs varying cryptographic algorithms. Quantum computing makes preserving data confidentiality across asymmetric infrastructure more difficult. However, exploiting the architecture of classical cryptographic schemes to integrate the post-quantum constructs could be used to maintain post-quantum level confidentiality over the Internet. This paper presents a post-quantum secure classical ABE-IBE proxy re-encryption scheme (L ABE-IBE PRE) that utilizes the classical ABE-IBE proxy re-encryption capabilities at the end nodes in a system and raises the data confidentiality to post-quantum secure level over the Internet. The proposed L ABE-IBE PRE transforms a ciphertext of the classical ABE scheme to a post-quantum secure ciphertext and from a post-quantum secure ciphertext to a ciphertext of the classical IBE scheme. We compare our proposed L ABE-IBE PRE scheme with classical ABE-IBE proxy re-encryption schemes, including Encryption Switching ABE-IBE (ES.ABE-IBE) scheme (He et al., 2019). We discuss the security and efficiency of our proposed scheme.
Attribute-based encryption (ABE) cryptography is widely known for its potential to solve the scalability issue of recent public key infrastructure (PKI). It provides a fine-grained access control system with high flexibility and efficiency by labeling the secret key and ciphertext with distinctive attributes. Due to its fine-grained features, the ABE scheme is a protection layer in securing users’ data and privacy in big data processing and analytics. However, quantum computing, new technology on the horizon that will transform the security and privacy environment, has begun to appear. Like the conventional ABE schemes, present cryptography is not excluded from the impacts of quantum technology as they are not made to be quantum-resistant. While most recent surveys generally touched on the generic features of attribute-based encryption schemes such as user revocation, scalability, flexibility, data confidentiality, and scope in pairing-based ABE schemes, this survey investigated quantum-resistant ABE schemes in securing big data. This survey reviews the challenges faced by the recent ABE cryptography in the post-quantum era and highlights its differences from the conventional pairing-based ABE schemes. Subsequently, we defined the criteria of an ideal quantum-resistant ABE scheme. Additionally, existing works on quantum-resistant ABE schemes are reviewed based on their algorithms design, security and functionalities. Lastly, we summarized quantum-resistant ABE schemes’ ongoing challenges and future works.
In proxy re-encryption schemes, a semi-trusted entity called a proxy can convert a ciphertext encrypted for Alice into a new ciphertext for Bob without seeing the underlying plaintext. Several proxy re-encryption schemes have been proposed, however, only two schemes which enables the conversion of IBE ciphertexts to PKE ciphertexts has been proposed. One of schemes has some drawbacks such that the size of the re-encrypted ciphertext increases and Bob must be aware of existence of the proxy, which means Bob cannot decrypt a re-encrypted ciphertext with same PKE decryption algorithm. The other one achieves security under Selective-ID model. We propose a new, efficient scheme that enables the conversion of IBE ciphertexts to PKE ciphertexts, and prove full-ID CPA security in the standard model. In our scheme, the size of the re-encrypted ciphertext is optimal and Bob should not aware of existence of the proxy. As far as we know, this is the first IBE-PKE type scheme that holds the above properties.
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.
As an extension to conditional proxy re-encryption, fuzzy conditional proxy re-encryption allows for a proxy to re-encrypt a ciphertext only if it satisfies some t-out-of-d threshold condition. Therefore, it is more desirable in some applications where fine-grained control of the decryption delegation is required. In this paper, we construct the first lattice-based fuzzy conditional proxy re-encryption scheme as a post-quantum alternative to this primitive. In our construction, original ciphertexts and re-encryption ciphertexts have the same form, thus only one decryption algorithm is needed for both kinds of ciphertexts. We formalize its security model and prove that it is selective secure under the LWE assumption.
Confidentiality in our digital world is based on the security of cryptographic algorithms. These are usually executed transparently in the background, with people often relying on them without further knowledge. In the course of technological progress with quantum computers, the protective function of common encryption algorithms is threatened. This particularly affects public-key methods such as RSA and DH based on discrete logarithms and prime factorization. Our concept describes the transformation of a classical asymmetric encryption method to a modern complexity class. Thereby the approach of CramerShoup is put on the new basis of elliptic curves. The system is provable cryptographically strong, especially against adaptive chosen-ciphertext attacks. In addition, the new method features small key lengths, making it suitable for Internet-of-Things. It represents an intermediate step towards an encryption scheme based on isogeny elliptic curves. This approach shows a way to a secure encryption scheme for the post-quantum computing era.
Once a cryptographically relevant quantum computer is built, confidential information that is communicated today can be decrypted and exposed. Key exchange methods currently used can then be broken and the key used to protect the data can be recovered. Depending on the duration for which information needs to remain confidential, quantum-safe solutions have to be used now to protect data transmitted today. In this paper, we review recent advances in integrating the combination of two different quantum-safe solutions, Quantum Key Distribution (QKD) and Post-Quantum Cryptography (PQC), in existing protocols. We also combine classical cryptography, PQC and QKD to securely exchange a key that remains secure even if only one of the three key exchange methods is secure. This is one of the first steps to update existing communication methods such that they remain secure even if only one of PQC, QKD or classical cryptography is secure.