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Length-preserving encryption based on single-key tweakable block cipher. (English) Zbl 1443.94086
Baek, Joonsang (ed.) et al., Provable security. 12th international conference, ProvSec 2018, Jeju, South Korea, October 25–28, 2018. Proceedings. Cham: Springer. Lect. Notes Comput. Sci. 11192, 313-326 (2018).
Summary: We present a single-key length doubler built on an $$n$$-bit tweakable block cipher (SLDT), which is a length-preserving cipher on the strings with bit length in integer interval $$\left[n,n+1,\ldots,2n-1\right]$$. SLDT is mainly motivated to reduce the key material size of a length doubler proposed by Y.-L. Chen et al. at FSE 2018 [Efficient length doubling from tweakable block ciphers. IACR Trans. Symmetric Cryptol. 2017, No. 3, 253–270 (2017), doi:0.13154/tosc.v2017.i3.253-270], since the key management is always challenging in practice. We prove that SLDT is a strong pseudo-random permutation (SPRP) if the underlying tweakable block cipher is SPRP.
For the entire collection see [Zbl 1398.94007].
##### MSC:
 94A60 Cryptography
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