Current research often focuses on the design of new methods that extend the well-established role of biometrics in authentication and identification into key management and cryptography. Methods have been proposed that involve biometric-governed access to cryptographic keys, as well as methods that utilize biometric samples to derive keys for specialized encryption algorithms. The aim of this paper is to present a possible method for random number generation from repeated measurements of fingerprints as an alternative approach to the proposed applications of biometrics in cryptography, and to analyze some of its properties. Such method could provide a valuable source of ranomness in mobile devices equipped with a fingerprint scanner.