[Paper Review] A One-Time Pad based Cipher for Data Protection in Distributed Environments

Igor Sobrado|ArXiv.org|May 24, 2000

Distributed systems and fault tolerance24 references3 citations

TL;DR

This paper proposes a one-time pad-based cipher for securing mobile code in distributed environments, enabling both data confidentiality and integrity without relying on shared keys. By combining a random codeword with message digests and using non-interactive, symmetric-like encryption, the scheme resists brute-force attacks and prevents malicious hosts from altering or concealing data, ensuring only authorized parties can modify or verify information.

ABSTRACT

A one-time pad (OTP) based cipher to insure both data protection and integrity when mobile code arrives to a remote host is presented. Data protection is required when a mobile agent could retrieve confidential information that would be encrypted in untrusted nodes of the network; in this case, information management could not rely on carrying an encryption key. Data integrity is a prerequisite because mobile code must be protected against malicious hosts that, by counterfeiting or removing collected data, could cover information to the server that has sent the agent. The algorithm described in this article seems to be simple enough, so as to be easily implemented. This scheme is based on a non-interactive protocol and allows a remote host to change its own data on-the-fly and, at the same time, protecting information against handling by other hosts.

Motivation & Objective

• To address the security vulnerability of mobile agents in untrusted distributed environments where hosts may alter or conceal collected data.
• To eliminate reliance on shared or transmitted encryption keys, which are impractical in mobile code scenarios.
• To provide a lightweight, efficient cryptographic solution that resists cryptanalysis and brute-force attacks.
• To ensure data integrity by allowing only authorized hosts (server and data-providing host) to modify or authenticate information.
• To enable on-the-fly data modification by remote hosts while protecting data from unauthorized access or tampering.

Proposed method

• The scheme uses a 128-bit random codeword combined with a message digest (MFD) to form a 128-bit signature, ensuring uniqueness and resistance to forgery.
• Data is encrypted using a one-time pad-like mechanism where the key is derived from a combination of the codeword and message, preventing pattern leakage.
• The algorithm applies bitwise XOR and rotation operations (e.g., $f \ll n$, $f \gg n$) to obscure data structure and statistical patterns.
• A non-interactive protocol allows remote hosts to update data in real time, with signatures binding the data to its source and time of creation.
• The use of a codeword ensures that even if the message is altered, the signature will not validate unless the correct codeword is known.
• Digital signatures are generated using 128-bit keys, which can be transmitted over untrusted channels, while encryption keys remain protected via secure channels.

Experimental results

Research questions

• RQ1 How can mobile agents ensure data integrity when executing on untrusted remote hosts that may tamper with collected information?
• RQ2 Can a one-time pad-based system provide strong confidentiality and integrity without requiring key exchange in distributed mobile code environments?
• RQ3 What mechanisms can prevent malicious hosts from removing or falsifying data collected by mobile agents?
• RQ4 How can data be updated securely on remote hosts without exposing encryption keys?
• RQ5 What cryptographic properties are necessary to prevent brute-force or statistical cryptanalysis in mobile code systems?

Key findings

• The proposed cipher provides strong resistance to brute-force attacks, as the 128-bit codeword and signature space make guessing the correct key infeasible, with only a 1 in $2^{64}$ chance of success per attempt.
• The scheme ensures data integrity by binding each message to a unique signature that includes a random codeword, making forgery computationally infeasible.
• The algorithm is efficient and suitable for mobile code execution, as it avoids the high computational cost of public-key cryptography while maintaining strong security guarantees.
• The method prevents statistical analysis by destroying predictable patterns in the data through bitwise operations and randomization.
• Only the server that originated the mobile agent and the host that provided the data can modify or authenticate the information, ensuring access control and accountability.
• The system supports dynamic data updates on remote hosts without requiring re-establishment of secure channels or key exchange, enabling real-time data handling in untrusted environments.