2,617 research outputs found
Information Theoretic Security for Broadcasting of Two Encrypted Sources under Side-Channel Attacks
We consider the secure communication problem for broadcasting of two
encrypted sources. The sender wishes to broadcast two secret messages via two
common key cryptosystems. We assume that the adversary can use the
side-channel, where the side information on common keys can be obtained via the
rate constraint noiseless channel. To solve this problem we formulate the post
encryption coding system. On the information leakage on two secrete messages to
the adversary, we provide an explicit sufficient condition to attain the
exponential decay of this quantity for large block lengths of encrypted
sources.Comment: 13 pages, 4 figures. In the current version we we have corrected
errors in Fig. 2 and Fig. 4. arXiv admin note: substantial text overlap with
arXiv:1801.02563, arXiv:1801.0492
Error Free Perfect Secrecy Systems
Shannon's fundamental bound for perfect secrecy says that the entropy of the
secret message cannot be larger than the entropy of the secret key initially
shared by the sender and the legitimate receiver. Massey gave an information
theoretic proof of this result, however this proof does not require
independence of the key and ciphertext. By further assuming independence, we
obtain a tighter lower bound, namely that the key entropy is not less than the
logarithm of the message sample size in any cipher achieving perfect secrecy,
even if the source distribution is fixed. The same bound also applies to the
entropy of the ciphertext. The bounds still hold if the secret message has been
compressed before encryption.
This paper also illustrates that the lower bound only gives the minimum size
of the pre-shared secret key. When a cipher system is used multiple times, this
is no longer a reasonable measure for the portion of key consumed in each
round. Instead, this paper proposes and justifies a new measure for key
consumption rate. The existence of a fundamental tradeoff between the expected
key consumption and the number of channel uses for conveying a ciphertext is
shown. Optimal and nearly optimal secure codes are designed.Comment: Submitted to the IEEE Trans. Info. Theor
Roadmap on optical security
Postprint (author's final draft
Distributed Source Coding with Encryption Using Correlated Keys
We pose and investigate the distributed secure source coding based on the
common key cryptosystem. This cryptosystem includes the secrecy amplification
problem for distributed encrypted sources with correlated keys using
post-encryption-compression, which was posed investigated by Santoso and
Oohama. In this paper we propose another new security criterion which is
generally more strict compared to the commonly used security criterion which is
based on the upper-bound of mutual information between the plaintext and the
ciphertext. Under this criterion, we establish the necessary and sufficient
condition for the secure transmission of correlated sources.Comment: 7 pages, 3 figure. The short version was submitted to ISIT 2021. We
have some typos in the short version. Those are fixed in this version. arXiv
admin note: text overlap with arXiv:1801.0492
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