Re-visiting the One-Time Pad

Publication Type:

Journal Articles


International Journal of Network Security, Volume 6, Number 1, p.94–102 (2008)



One time pad, Perfect secrecy, Private-key cryptography, Private-object cryptography, Shannon security


In 1949, Shannon proved the perfect secrecy of the Vernam cryptographic system (One-Time Pad or OTP). It has generally been believed that the perfectly random and uncompressible OTP which is transmitted needs to have a length equal to the message length for this result to be true. In this paper, we prove that the length of the transmitted OTP actually contains useful information and could be exploited to compress the transmitted-OTP while retaining perfect secrecy. The message bits can be interpreted as True/False statements about the OTP, a private object, leading to the notion of private object cryptography.


Copyright of this article belongs to International Journal of Network Security.