# Creating Unsigned Transactions

All API requests that create a new transaction will accept either a *secretPhrase* or a *publicKey* parameter:

* If *secretPhrase* is supplied, a transaction is created, signed at the server, and broadcast by the server as usual.
* If only a *publicKey* parameter is supplied as a 64-digit (32-byte) hex string, the transaction will be prepared by the server and returned in the JSON response as *transactionJSON* without a signature. This JSON object along with *secretPhrase* can then be supplied to Sign Transaction as *unsignedTransactionJSON* and the resulting signed *transactionJSON* can then be supplied to Broadcast Transaction. This sequence allows for offline transaction signing so that *secretPhrase* never needs to be exposed.
* *unsignedTransactionBytes* may be used instead of unsigned *transactionJSON* when there is no encrypted message. Messages to be encrypted require the *secretPhrase* for encryption and so cannot be included in *unsignedTransactionBytes*.