摘要 |
Encryption is a common tool to achieve privacy of communication in networks whose lines are not physically protected. In most communication networks, however, having a sender S send an encrypted message to a recipient R does not hide the very fact that S has sent a message to R, and this may in itself constitute valuable information that the parties would rather keep confidential. A transmission method is described that (1) keeps the identities of senders and receivers confidential, but (2) can trace senders and receivers under certain given circumstances.
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