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Instead, put it somewhere like /etc/apt/keyrings/. Now that you have your converted key, do not add it to apt's trusted keystore by copying it into /etc/apt//. gpg supports a number of key formats, so if your key is in a different format, convert it by importing it into a temp keyring, then exporting it again:.Verify that the filetype is "PGP public key block Public-Key (old)":.(No need for -O or > wget defaults to saving the file in your current directory with the same filename it has on the server.) I'll reiterate them here (cleaned up slightly) so all the steps are consolidated in one place: The instructions given in Ugo Delle Donne's answer for converting the key to the (legacy) keyring v4 format that apt will accept are correct and helpful, but that's only half of the solution. You can use apt-cache policy to inspect the current pin priorities, and if needed you can adjust pinning based on origin to achieve this effect. Apt's default pinning rules give higher priority to official distro repos, which (in conjunction with proper key management) offers some protection against third-party repos replacing distro-provided packages. What we want to do instead is configure apt to accept signatures from a third-party repository only on packages being installed from that repository - no cross-signing. This weakens the assurance provided by the package signing mechanism against malicous packages being injected into the official Ubuntu mirrors network. This means that when installing any package from any repo (including the official distro repos), apt will happily accept the package being signed by any of those trusted keys (whether the key belongs to the repository the package is coming from or not). The problem is that any key you add to either of the above is completely and unconditionally trusted by apt. These two things are equivalent, and doing either one is a huge security risk. The problem is not a question of appending a key to one big keyring file etc/apt/trusted.gpg vs manually putting single-key keyring files into the directory /etc/apt//. You need to know why apt-key add is deprecatedĪll of the answers so far work around the symptom ("Don't use apt-key add") but fail to address the actual problem that led to apt-key add being deprecated.
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