sha3: have ShakeHash extend hash.Hash

Package sha3 recommends the SHAKE functions for new uses, but this is
currently somewhat inconvenient because ShakeHash does not implement
hash.Hash. This is understandable, as SHAKE supports arbitrary-length
outputs whereas hash.Hash only supports fixed-length outputs. But
there's a natural fixed-length output to provide: the minimum output
that still provides SHAKE's full-strength generic security.

While here, tweak Sum so that its temporary buffer can be stack

Also, tweak the panic message in Write so that the error text is more
readily understandable to Go programmers without needing to be
familiar with crypto jargon, and add a similar check in Sum.

Change-Id: Icf037d3990a71de5630f8825606614443f8c5245
LUCI-TryBot-Result: Go LUCI <>
Reviewed-by: Adam Langley <>
Auto-Submit: Matthew Dempsky <>
3 files changed
tree: 8fe050a8c6dd303fd8cdfc140af062c25ae762f1
  1. acme/
  2. argon2/
  3. bcrypt/
  4. blake2b/
  5. blake2s/
  6. blowfish/
  7. bn256/
  8. cast5/
  9. chacha20/
  10. chacha20poly1305/
  11. cryptobyte/
  12. curve25519/
  13. ed25519/
  14. hkdf/
  15. internal/
  16. md4/
  17. nacl/
  18. ocsp/
  19. openpgp/
  20. otr/
  21. pbkdf2/
  22. pkcs12/
  23. poly1305/
  24. ripemd160/
  25. salsa20/
  26. scrypt/
  27. sha3/
  28. ssh/
  29. tea/
  30. twofish/
  31. x509roots/
  32. xtea/
  33. xts/
  34. .gitattributes
  35. .gitignore
  36. codereview.cfg
  38. go.mod
  39. go.sum

Go Cryptography

Go Reference

This repository holds supplementary Go cryptography libraries.


The easiest way to install is to run go get -u You can also manually git clone the repository to $GOPATH/src/

Report Issues / Send Patches

This repository uses Gerrit for code changes. To learn how to submit changes to this repository, see

The main issue tracker for the crypto repository is located at Prefix your issue with “x/crypto:” in the subject line, so it is easy to find.

Note that contributions to the cryptography package receive additional scrutiny due to their sensitive nature. Patches may take longer than normal to receive feedback.