If the server's capable to decrypt the data, unless you use a trusted HSM that keeps an audit trail, it generally doesn't make sense to encrypt in the first pla

If the server's capable to decrypt the data, unless you use a trusted HSM that keeps an audit trail, it generally doesn't make sense to encrypt in the first place. Especially with anything resource-intensive. When the server has everything to decrypt the data, the encryption only does the obfuscation, not any strong protection. Otherwise, if we talk about - just for example - a receiving mail server (MDA) that has encrypted mailbox storage like [1], then it really depends on how much mail you receive. For a typical personal mailbox, where the steady rate is less than an email-per-minute (and usual email size is some kilobytes, not megabytes), encryption overhead is negligible. Such server would sleep most of time anyway. [1]: https://grepular.com/Automatically_Encrypting_all_Incoming_Email https://grepular.com/Automatically_Encrypting_all_Incoming_E...