Add support for truncated PBKDF2-HMAC-SHA1 hashes
@lokkju is already working on this.
Since Jan 10, 2022.
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Description
In preparation for adding support for extracting and cracking Chrome Sync's custom passwords from the local profile's Nigori.bin file, I'd like to add support for truncated PBKDF2-HMAC-SHA1 hashes. Currently, the format only seems to support 20 byte hash lengths, though the PBKDF2HMAC algorithm supports any length up to 20 bytes. Chrome Sync's Nigori keys only use and store 16 bytes of keying material.
As suggested on the mailing list, I've added support for the pbkdf2-hmac-sha1 format to dynamically determine the key length. This should support keys from 8 (max ARCH_SIZE, to optimize cmp_all) to 20 bytes, including purposefully short or accidentally truncated hashes.
I've added support for the cpu code paths; I haven't (and probably won't) mess with opencl at the moment.
If the approach sounds good, I'll open a pull request for pbkdf-hmac-sha1-truncated-hash-support-cpuonly
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