Attempting to DECRYPT a cipher message using the Apple API SecKeyCreateDecryptedData(privateKey, .rsaEncryptionOAEPSHA256, encryptedMessage). Decryption ALWAYS fails for every algorithm. SecKeyCreateDecryptedDataWithParameters Error: `Domain=NSOSStatusErrorDomain Code=-50 "algid:encrypt:RSA:OAEP:SHA256: algorithm not supported by the key <SecKeyRef:('com.yubico.Authenticator.TokenExtension:5621CDF8560D4C412030886584EC4C9E394CC376DD9738B0CCBB51924FC26EB6') 0x3007fd150>" UserInfo={numberOfErrorsDeep=0, NSDescription=algid:encrypt:RSA:OAEP:SHA256: algorithm not supported by the key <SecKeyRef:('com.yubico.Authenticator.TokenExtension:5621CDF8560D4C412030886584EC4C9E394CC376DD9738B0CCBB51924FC26EB6') 0x3007fd150>}` Decryption failed: SecKeyCreateDecryptedData returned nil. Error: One or more parameters passed to a function were not valid. When checking with SecKeyIsAlgorithmSupported(privateKey, .decrypt, <ANYalgorithm>) all algorithms fail. Btw - The privateKey does support decryption when retrieving the attributes. Important to know: The private key is a reference to an external private key placed in the iOS Keychain via a 3rd party CryptoTokenKit Extension app. When I perform, the SecKeyCreateSignature(...) and pass in the SAME privateKey reference, the OS automatically calls the 3rd party app to perform a successful signing with the private key that reside on a YubiKey. Here's my code for obtaining the private key reference from an Identity: func getKeyPairFromIdentity() -> (privateKey: SecKey, publicKey: SecKey)? { let query = NSDictionary( dictionary: [ kSecClass as String: kSecClassIdentity, kSecAttrTokenID as String: self.tokenID!, kSecReturnRef as String: kCFBooleanTrue as Any ] ) var identityRef: CFTypeRef? let status = SecItemCopyMatching(query, &identityRef) if status == errSecSuccess, let identity = identityRef { var privateKeyRef: SecKey? let keyStatus = SecIdentityCopyPrivateKey(identity as! SecIdentity, &privateKeyRef) if keyStatus == errSecSuccess, let privateKey = privateKeyRef { let publicKey = SecKeyCopyPublicKey(privateKey) if let publicKey = publicKey { print("Private and public keys extracted successfully.") return (privateKey, publicKey) } else { print("Failed to extract public key from private key.") return nil } } else { print("SecIdentityCopyPrivateKey: Private key not found error: \(keyStatus)") return nil } } else { print("SecIdentity not found or error: \(status)") return nil } }