script: Use base64ct instead of base64 in SubtleCrypto
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The `SubtleCrypto` interface of WebCrypto API needs to encode and decode keys in base64 alphabets when exporting/importing keys in JsonWebKey format. We currently use the `base64` crate to handle base64 encoding and decoding. This patch switches to use the `base64ct` crate which is a constant-time implementation of base64 alphabets. Using constant-time implementation to handle base64 encoding and decoding of cryptographic secret provides a better protection from time-based sidechannel attack. Remarks: The multi-line changes in `ecdh_operation.rs` are mostly caused by `./mach fmt`. Signed-off-by: Kingsley Yung <kingsley@kkoyung.dev>
yezhizhen
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Nov 3, 2025
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Yes. It doesn't include a data-related heuristic for maintaining constant runtime, making it less efficient than Therefore, I only made these changes to the WebCrypto API code. Other parts of servo still use |
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The
SubtleCryptointerface of WebCrypto API needs to encode and decode keys in base64 alphabets when exporting/importing keys in JsonWebKey format.We currently use the
base64crate to handle base64 encoding and decoding. This patch switches to use thebase64ctcrate, which is a constant-time implementation of base64 alphabets.Using constant-time implementation to handle base64 encoding and decoding of cryptographic secret provides a better protection against time-based sidechannel attack.
Remarks: The multi-line changes in
ecdh_operation.rsare mostly caused by./mach fmt.Testing: Refactoring. Existing tests suffice.