Encrypt packets in-place#1787
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Rob-Hague merged 1 commit intosshnet:developfrom May 5, 2026
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Support in-place encryption in the cipher types, then use it on the plaintext packets instead of allocating a new array each time. Removes 2 of 4 bytes allocated for each byte uploaded over SFTP. For AES-CTR, supporting in-place encryption in this case means adding a persistent buffer for the keystream and encrypting in chunks. The performance difference is ~1-2% i.e. marginal versus one-shotting it. The variance is similar also for different choices of buffer size (here 4096 is used).
Rob-Hague
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PR#1752 added a persistent buffer into which to decrypt packets, rather than allocating a new array for each packet. This was on the back of sshnet#1733 which added support in the cipher types for decrypting into a given buffer, but for the case of AES-CTR, not into the same buffer in-place. sshnet#1787 adds that missing support, meaning we can now decrypt in-place and remove the plaintext buffer.
Rob-Hague
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sshnet#1752 added a persistent buffer into which to decrypt packets, rather than allocating a new array for each packet. This was on the back of sshnet#1733 which added support in the cipher types for decrypting into a given buffer, but for the case of AES-CTR, not into the same buffer in-place. sshnet#1787 adds that missing support, meaning we can now decrypt in-place, and the plaintext buffer becomes unnecessary.
WojciechNagorski
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May 5, 2026
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Rob-Hague
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May 5, 2026
sshnet#1752 added a persistent buffer into which to decrypt packets, rather than allocating a new array for each packet. This was on the back of sshnet#1733 which added support in the cipher types for decrypting into a given buffer, but for the case of AES-CTR, not into the same buffer in-place. sshnet#1787 adds that missing support, meaning we can now decrypt in-place, and the plaintext buffer becomes unnecessary.
Rob-Hague
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May 5, 2026
#1752 added a persistent buffer into which to decrypt packets, rather than allocating a new array for each packet. This was on the back of #1733 which added support in the cipher types for decrypting into a given buffer, but for the case of AES-CTR, not into the same buffer in-place. #1787 adds that missing support, meaning we can now decrypt in-place, and the plaintext buffer becomes unnecessary.
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Support in-place encryption in the cipher types, then use it on the plaintext packets instead of allocating a new array each time. Removes 2 of 4 bytes allocated for each byte uploaded over SFTP.
For AES-CTR, supporting in-place encryption in this case means adding a persistent buffer for the keystream and encrypting in chunks. The performance difference is ~1-2% i.e. marginal versus one-shotting it. The variance is similar also for different choices of buffer size (here 4096 is used).