Embodiments of methods and systems for producing random values include a first module that provides a random data request (e.g., a request for an unspecified length of random data) to a random number generator. The random number generator generates random data in response to the random data request, and multiple random values derived from the random data are stored in a buffer. In response to receiving a request for a random value (e.g., an initialization vector), the first module produces the random value based on the multiple random values stored in the buffer. The system also may be configured to receive requests for other types of random values, and to fulfill those requests using random data that is not buffered (e.g., random data that is received directly from the random number generator in response to a request for a specified length of random data).