International Association for Cryptologic Research

International Association
for Cryptologic Research

CryptoDB

Sunder Lal

Publications

Year
Venue
Title
2010
EPRINT
Efficient Generalized Signcryption Schemes
Prashant Kushwah Sunder Lal
Generalized signcryption is a new cryptographic primitive which works as a signcryption scheme, a signature scheme and an encryption scheme as per need. Recently Ji et al. proposed a security model for certificateless generalized signcryption scheme and also proposed a scheme which they claim is secure under the proposed security model. In this paper we show that Ji et al. scheme is not existentially unforgeable against Type-I adversary and propose a simplified certificateless generalized signcryption. We also present an efficient identity based generalized signcryption scheme.
2008
EPRINT
Identity Based Strong Bi-Designated Verifier Proxy Signature Schemes
Sunder Lal Vandani Verma
Proxy signature schemes allow delegation of signing rights. The paper proposes the notion of Identity Based Strong Bi-Designated Verifier Proxy Signature (ID-SBDVPS) schemes. In such schemes, only the two designated verifiers can verify that the proxy signer on behalf of the original signer signed the message but none of them is able to convince anyone else of this fact. The paper proposes nine such schemes and analyses the computational efficiency of each.
2008
EPRINT
Multi-PKG ID based signcryption
Sunder Lal Prashant Kushwah
Here we propose an identity based signcryption scheme in the multi-PKG environment where sender and receiver receive public key from different PKG. We also define security models for our scheme and give security proofs in random oracle model.
2008
EPRINT
ID based generalized signcryption
Sunder Lal Prashant Kushwah
Generalized signcryption is a new cryptographic primitive in which a signcryption scheme can work as an encryption scheme as well as a signature scheme. This paper presents an identity based generalized signcryption scheme based on bilinear pairing and discusses its security for message confidentiality non repudiation and ciphertext authentication.
2007
EPRINT
Some Identity Based Strong Bi-Designated Verifier Signature Schemes
Sunder Lal Vandani Verma
The problem of generalization of (single) designated verifier schemes to several designated verifiers was proposed by Desmedt in 2003. The paper proposes eight new Identity Based Strong Bi-Designated Verifier Signature Schemes in which the two designated verifiers may not know each other. The security and the computational efficiency of the schemes are also analyzed.
2007
EPRINT
SECURITY PROOF FOR SHENGBAO WANG’S IDENTITY-BASED ENCRYPTION SCHEME
Sunder Lal Priyam Sharma
This paper analyzes the security of an IBE scheme proposed by Wang in 2007. It is shown that under BDHP (which is polynomially time equivalent to BIDHP) assumption the scheme is secure in random oracle model.
2007
EPRINT
REMARKS ON IBE SCHEME OF WANG AND CAO
Sunder Lal Priyam Sharma
In this paper we analyze and find an anomaly in the security proof of the identity-based encryption (IBE) scheme fullM-IBE of Wang and Cao [9], which is based on mBDHP. Here we give another proof for fullM-IBE which is based on Bilinear Diffie-Hellman Problem (BDHP). We also obtain a tightness improvement using a stronger assumption, namely, the Bilinear Inverse Dicision Diffie-Hellman problem (BIDDHP).
2007
EPRINT
An Improved Remote User Authentication Scheme using Bilinear Pairings
Sunder Lal K.K.Goyal
In 2005 Das et al. [5] proposed a remote user authentication scheme using bilinear pairings. Fang and Huang [7] analyzed the scheme and pointed out some weaknesses. They also proposed an improvement. Recently, Giri and Srivastava [9] observed that the improved scheme is still insecure to off-line attack and an improvement. However, the improved scheme is still insecure. In this paper, we show some weaknesses in the existing scheme and propose an improvement. The proposed scheme also enables users to choose and change the password without the help of the remote server.
2006
EPRINT
Identity Based Strong Designated Verifier Proxy Signature Schemes
Sunder Lal Vandani Verma
The paper proposes four new ID based strong designated verifier proxy signature (SDVPS) scheme. The schemes are formed by introducing proxy in ID based SDVS, ID based in SDVPS and ID based proxy in SDVS. We have also analyzed the security of the schemes and their computation aspects.
2004
EPRINT
ID-based Ring Signature and Proxy Ring Signature Schemes from Bilinear Pairings
Amit K Awasthi Sunder Lal
n 2001, Rivest et al. firstly introduced the concept of ring signatures. A ring signature is a simplified group signature without any manager. It protects the anonymity of a signer. The first scheme proposed by Rivest et al. was based on RSA cryptosystem and certificate based public key setting. The first ring signature scheme based on DLP was proposed by Abe, Ohkubo, and Suzuki. Their scheme is also based on the general certificate-based public key setting too. In 2002, Zhang and Kim proposed a new ID-based ring signature scheme using pairings. Later Lin and Wu proposed a more efficient ID-based ring signature scheme. Both these schemes have some inconsistency in computational aspect. In this paper we propose a new ID-based ring signature scheme and a proxy ring signature scheme. Both the schemes are more efficient than existing one. These schemes also take care of the inconsistencies in above two schemes.
2004
EPRINT
Security Analysis of A Dynamic ID-based Remote User Authentication Scheme
Amit K Awasthi Sunder Lal
Since 1981, when Lamport introduced the remote user authentication scheme using table, a plenty of schemes had been proposed with table and without table using. Recently Das, Saxena and Gulati have proposed A dynamic ID-based remote user authentication scheme. They claimed that their scheme is secure against ID-theft, and can resist the reply attacks, forgery attacks, and insider attacks and so on. In this paper we show that Das et al.?s scheme is completely insecure and using of this scheme is equivalent to an open server access without any password.
2003
EPRINT
Proxy Blind Signature Scheme
Amit K Awasthi Sunder Lal
Blind signature is the concept to ensure anonymity of e-coins. Untracebility and unlinkability are two main properties of real coins, which require mimicking electronically. Whenever a user is permitted to spend an e-coin, he is in need to fulfill above requirements of blind signature. This paper proposes a proxy blind signature scheme with which a proxy is able to make proxy blind signature which verifier is able to verify in a way similar to proxy signature schemes.
2003
EPRINT
A Scheme for obtaining a Warrant Message from the Digital Proxy Signatures
Sunder Lal Amit K Awasthi
Mambo et al [6-7] introduced a proxy signature scheme. Neuman [8] extended the scheme for delegation by warrant, which was further extended by Kim et al [4] to partial delegation with a warrant. In this paper we propose a new type of digital proxy signature scheme in which the warrant message can be recovered from the proxy signature. In this scheme the warrant message is conveyed within the proxy signature and recovered by the verifier, i.e., the warrant need not be hashed or sent along with the proxy signature. It saves both communication bandwidth and storage space.