The CryptoKey.extractable read-only property that indicates if the raw material key can be extracted, for example for archiving it. Syntax result = key.extractable Return value result is a Boolean indicating if the key can be extracted. Specifications Specification Status Comment Web Cryptography APIThe definition of 'CryptoKey.extractable' 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 and Crypto.subtle. CryptoKey, the interface it belongs to.