TO DO

Interfaces

• lazy loading for crypto factories?
• digests
  • support keys (eg blake)
  • support XOFs
• add factory-version
• protect unsafe method names

pk sign padding: PSS "requires" saltlength param

• add '(pss <saltlength>) pad mode
• max size: https://github.com/pyca/cryptography/issues/3008

Misc impl

• libcrypto: other standard output formats

Nettle

• add pkey RSA OAEP support? (need rkt impl of OAEP)

GCrypt

• add PSS saltlen support (needs gcrypt >= 1.7.0)
  • https://lwn.net/Articles/684508/
• shake128 digest has no fixed length