Dual RSA and Its Security Analysis

We present new variants of an RSA whose key generation algorithms output two distinct RSA key pairs having the same public and private exponents. This family of variants, called dual RSA, can be used in scenarios that require two instances of RSA with the advantage of reducing the storage requirements for the keys. Two applications for dual RSA, blind signatures and authentication/secrecy, are proposed. In addition, we also provide the security analysis of dual RSA. Compared to normal RSA, the security boundary should be raised when applying dual RSA to the types of small-d, small-e, and rebalanced-RSA.