Hydrolyzes the N-acetamido groups of N-acetyl-D-glucosamine residues in chitin to form chitosan and acetate (PubMed:17400891). Chitosan is required to anchor melanin to the cell wall, for maintenance of cell wall integrity, and for proper cytokinesis (PubMed:17400891). Chitosan offers an advantage during infection as it is less readily detected than chitin by host immunosurveillance mechanisms (PubMed:21784998, PubMed:32071275, PubMed:27165801). [(1->4)-N-acetyl-beta-D-glucosaminyl](n) + n H2O = n acetate + chitosan Expressed during unicellular vegetative growth. Repressed by the antifungal agent caspofungin. Inoculation of live or dead cells in mouse leads to an aberrant host hyperinflammatory immune response and host death (PubMed:32071275). Triple knockout of CDA1, CDA2 and CDA3 results in an absence of cell wall chitosan, melanization of surrounding media, an increase in capsule size, sensitivity to cell wall (sodium dodecyl sulfate), osmotic (NaCl) and heat stress, and avirulence in a mouse intranasal infection model (PubMed:17400891, PubMed:21784998, PubMed:32071275, PubMed:27165801, PubMed:22354955). A strain lacking CDA1, CDA2, and CDA3 is a potential vaccine candidate; inoculation with heat-killed CDA1-CDA2-CDA3 knockout cells in mouse induces protective immunity to subsequent virulent fungal infection. Belongs to the polysaccharide deacetylase family. The protein characterized in PubMed:10749672 is not a chitin deacetylase, the peptides sequenced being copurified contaminants of the protein under study.