The Crypto.subtle read-only property returns a SubtleCrypto object allowing to perform cryptographical operations. Syntax var crypto = crypto.subtle; Specifications Specification Status Comment Web Cryptography APIThe definition of 'Crypto.subtle' in that specification. Candidate Recommendation Initial definition. Browser compatibility Desktop Mobile Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari Basic support 37 34 (34) Not supported ? Not supported Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Basic support (Yes) 37 34.0 (34) Not supported ? Not supported See also Crypto. SubtleCrypto.