One of the earliest models of weak randomness is the Chor-Goldreich (CG) source. A (t,n,k)-CG source is a sequence of random variables \mathbf{X}=(\mathbf{X}_1,\dots,\mathbf{X}_t) \sim (\{0,1\}^n)^t, where each \mathbf{X}_i has min-entropy k conditioned on any fixing of \mathbf{X}_1,\dots,\mathbf{X}_{i-1}. Chor and Goldreich proved that there is no deterministic way to extract randomness ... more >>>

We investigate the task of deterministically condensing randomness from Online Non-Oblivious Symbol Fixing (oNOSF) sources, a natural model of defective random sources for which it is known that extraction is impossible [AORSV, EUROCRYPT'20]. A (g,\ell)-oNOSF source is a sequence of \ell blocks \mathbf{X} = (\mathbf{X}_1, \dots, \mathbf{X}_{\ell})\sim (\{0, 1\}^{n})^{\ell}, where ... more >>>