Zero byte operations #239
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Zero byte operations #239
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mattsb42-aws
requested changes
Jan 24, 2020
Regarding aws#237, the shape of the CryptoKey when dealing with a fallback may slightly differ. By changing all references to AwsEsdkJsCryptoKey I can control any type mismatch.
There are two sublte things going on here. First, in the case of a mixed backend, the non-zero backend should be the native implementation. I assert that it should be slightly harder to exfiltrate from the native implementation than a JS implementation. Second, if I force the import of the master key into only half of the mixed backend, then `getSubtleFunction` will complain about a mismatch. Because the crypto key and the backend are not both mixed. To resolve this the backend for the raw AES master key is issolated here.
See: aws#237 Since the WebCrypto decrypt API expects the AES-GCM tag with the encrypted data, zero bytes of encrypted data is not zero bytes of data. fix: Add tests Add tests to specificly cover the Mixed Backend conditions and logic.
The suite did not have a KDF, so this value was `undefined` which should never happen in practice. Tests should match expected situations.
Since MSRCrypto is a viable option for a falback, it must be usable. These differ from the WebCrypto API * The algorithm argument in importKey is passed through to the imported key. * The algorithm is normalize to lower case microsoft/MSR-JavaScript-Crypto#1
Adding an example of useing a fallback. This example uses MSRCrypto version 1.6.0.
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scottarc
approved these changes
Mar 26, 2020
mattsb42-aws
approved these changes
Mar 27, 2020
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Resolves #237
Several changes bundled together:
CryptoKeytoAwsEsdkJsCryptoKey'algorithm'algorithmargument forimportKeyBy submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.
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