  Quantum information scrambling is a unitary process that destroys local
correlations and spreads information throughout the system, effectively hiding
it in nonlocal degrees of freedom. In principle, unscrambling this information
is possible with perfect knowledge of the unitary dynamics [B. Yoshida and A.
Kitaev, arXiv:1710.03363.]. However, this Letter demonstrates that even without
previous knowledge of the internal dynamics, information can be efficiently
decoded from an unknown scrambler by monitoring the outgoing information of a
local subsystem. Surprisingly, we show that scramblers with unknown internal
dynamics, which are rapidly mixing but not fully chaotic, can be decoded using
Clifford decoders. The essential properties of a scrambling unitary can be
efficiently recovered, even if the process is exponentially complex.
Specifically, we establish that a unitary operator composed of $t$ non-Clifford
gates admits a Clifford decoder up to $t\le n$.
