# init(recipientKey:ciphersuite:info:presharedKey:presharedKeyIdentifier:) Creates a sender in preshared key (PSK) mode. ``` init(recipientKey: PK, ciphersuite: HPKE.Ciphersuite, info: Data, presharedKey psk: SymmetricKey, presharedKeyIdentifier pskID: Data) throws where PK : HPKEDiffieHellmanPublicKey ``` ## Parameters `recipientKey` The recipient’s public key for encrypting the messages. `ciphersuite` The cipher suite that defines the cryptographic algorithms to use. `info` Data that the key derivation function uses to compute the symmetric key material. The sender and the recipient need to use the same `info` data. `psk` A preshared key (PSK) that the sender and the recipient both hold. `pskID` An identifier for the PSK. ## Discussion The `Sender` encrypts messages in PSK mode using a symmetric encryption key that the sender and recipient both know in advance, in combination with a key it derives using a key derivation function (KDF) and the key schedule data in `info`. The `Sender` encapsulates the derived key using the recipient’s public key. You access the encapsulated key using [`encapsulatedKey`](/documentation/CryptoKit/HPKE/Sender/encapsulatedKey). > Note: The system throws errors from ``doc://com.apple.CryptoKit/documentation/CryptoKit/HPKE/Errors`` when it encounters them. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)