Proper SHA3 implementation?

[johanns]

Proper SHA3 implementation?

[iagox86]

It appears to be a padding issue.. NIST changed the padding to be:

SHA3-256(M) = K ECCAK [512] (M || 01, 256);

But this implementation doesn't account for the 01 bits in the padding. After padding the empty string, the first byte should be '06', not '01', to account for the extra 01 at the start (6 = 00000110, reversing endian = 01100000, the current padding is 10000......, but the proper padding is that one, 01 then 10000.......

[johanns]

@iagox86 This version of the gem is based on the original (optimized) C reference implementation released by Keccak team. I know that they have updated their implementation, and provide FIPS 202 support, but the gem's backing code MAY require a good amount of rewrite. Nonetheless, this is something I've been wanting to do, and I suppose it should be done sooner rather than later.

I'll look into this, but considering my schedule, I'm doubtful that I'll be able to complete a new release quickly (2 - 3 weeks would be optimistic). Of course, pull requests are welcome. :)

[johanns]

@iagox86 Quick update: I've managed to get SHA3-256 (FIPS 202) tests to pass. There is still quite a bit of work that needs to be done, but I should have it completed sooner than 2-weeks.

[iagox86]

Sweet, thanks!

On Wed, Oct 21, 2015 at 11:34 AM, Johanns Gregorian <
[email protected]> wrote:

@iagox86 https://github.com/iagox86 Quick update: I've managed to get
SHA3-256 (FIPS 202) tests to pass. There is still quite a bit of work that
needs to be done, but I should have it completed sooner than 2-weeks.

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#6 (comment).

[johanns]

@iagox86 I think it's done. I haven't cut a new gem yet, but you can grab a pre-release here:

https://github.com/johanns/sha3/releases/tag/v1.0.1

A few notes:

• There is no Keccak (non-FIPS) mode -- in other words, it's not backwards compatible (but fully SHA3 compliant). I didn't think this was necessary/required, and it was simpler to replace, rather than augment.
• I haven't implemented SHAKE128/256 functions, yet.

Let me know if this meets your expectations, and/or if you find any bugs.

[iagox86]

Awesome, I'll check it out! Thanks for the update!

On Thu, Oct 22, 2015 at 12:11 AM, Johanns Gregorian <
[email protected]> wrote:

@iagox86 https://github.com/iagox86 I think it's done. I haven't cut a
new gem yet, but you can grab a pre-release here:

https://github.com/johanns/sha3/releases/tag/v1.0.1

A few notes:

• There is no Keccak (non-FIPS) mode -- in other words, it's not
  backwards compatible (but fully SHA3 compliant). I didn't think this was
  necessary/required, and it was simpler to replace, rather than augment.
• I haven't implemented SHAKE128/256 functions, yet.

Let me know if this meets your expectations, and/or if you find any bugs.

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Reply to this email directly or view it on GitHub
#6 (comment).

[iagox86]

Just letting you know that (at least for what I'm doing), it's working perfectly!

[mmoghadas]

@iagox86 - Thanks for the feedback!