In order to cope with the problem of information leakage of existing secret-key agreement protocols under the environment of underwater acoustic channel (UAC), a covert secret-key agreement protocol called CSAP is proposed. In CSAP, the transmitter sends the uniformly distributed random messages to the receiver within a certain range of power constraints to ensure the reliability and the covertness of the protocol. The receiver calculates the estimated messages with Gibbs sampling according to the variance information of the underwater noise and uses the Log-Likelihood Ratio (LLR) test to extract the secret-key so as to reduce the uncertainty and the bit error rate (BER) of data transmission between two legitimate parties. The complexity of the CSAP protocol is ${O}$ ( ${n}$ ), where ${n}$ denotes the message length. The secrecy, covertness, and reliability of the CSAP protocol are proved by the information theory. The simulation results show that the CSAP protocol reduces the bit error rate (BER) by 28.88%, improves the secret-key generation rate by 25.70%, and decreases the communication cost by 11.32% on average compared to the existing protocol.

中文翻译：

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基于水下声学信道的隐秘密钥协议协议

为了解决现有密钥协商协议在水声信道（UAC）环境下的信息泄露问题，提出了一种称为CSAP的隐蔽密钥协商协议。在 CSAP 中，发送端在一定的功率约束范围内向接收端发送均匀分布的随机消息，以保证协议的可靠性和隐蔽性。接收机根据水下噪声的方差信息计算吉布斯采样估计消息，并使用对数似然比（LLR）测试提取密钥，以降低不确定性和误码率（BER）两个合法方之间的数据传输。CSAP 协议的复杂度为 ${O}$( ${n}$）， 在哪里 ${n}$表示消息长度。信息论证明了CSAP协议的保密性、隐蔽性和可靠性。仿真结果表明，与现有协议相比，CSAP协议的误码率（BER）降低了28.88%，密钥生成率提高了25.70%，通信成本平均降低了11.32%。