The CryptoKey interface represents a cryptographic key obtained from one of the SubtleCrypto methods.

CryptoKey.type The type of key the object represents. It may take one of the following values: “secret”, “private” or “public”.

CryptoKey.extractable A boolean value indicating whether or not the key may be extracted using SubtleCrypto.exportKey() or SubtleCrypto.wrapKey().

CryptoKey.algorithm An object describing the algorithm for which this key can be used and any associated extra parameters.

CryptoKey.usages An array of strings, indicating what can be done with the key. Possible values for array elements are “encrypt”, “decrypt”, “sign”, “verify”, “deriveKey”, “deriveBits”, “wrapKey”, and “unwrapKey”.

For more information on CryptoKey visit MDN Web Docs.