  In this paper, we address the finite Signal-to-Noise Ratio (SNR)
Diversity-Multiplexing Tradeoff (DMT) of the Multiple Input Multiple Output
(MIMO) wiretap channel, where a Zero-Forcing (ZF) transmit scheme, that intends
to send the secret information in the orthogonal space of the eavesdropper
channel, is used. First, we introduce the secrecy multiplexing gain at
finite-SNR that generalizes the definition at high-SNR. Then, we provide upper
and lower bounds on the outage probability under secrecy constraint, from which
secrecy diversity gain estimates of ZF are derived. Through asymptotic
analysis, we show that the upper bound underestimates the secrecy diversity
gain, whereas the lower bound is tight at high-SNR, and thus its related
diversity gain estimate is equal to the actual asymptotic secrecy diversity
gain of the MIMO wiretap channel.
