In cryptography, "wrapping a key" refers to exporting and then encrypting the keying material. The subtle.unwrapKey() method attempts to decrypt a wrapped key and create a <CryptoKey> instance. It is equivalent to calling subtle.decrypt() first on the encrypted key data (using the wrappedKey, unwrapAlgo, and unwrappingKey arguments as input) then passing the results in to the subtle.importKey() method using the unwrappedKeyAlgo, extractable, and keyUsages arguments as inputs. If successful, the returned promise is resolved with a <CryptoKey> object.
The wrapping algorithms currently supported include:
'RSA-OAEP''AES-CTR''AES-CBC''AES-GCM''AES-KW'
The unwrapped key algorithms supported include:
'RSASSA-PKCS1-v1_5''RSA-PSS''RSA-OAEP''ECDSA''Ed25519''Ed448''ECDH''X25519''X448''HMAC''AES-CTR''AES-CBC''AES-GCM''AES-KW'