3 Commits

Author SHA1 Message Date
Janos Follath
08a4aebc46 HKDF: Add warning to partial functions
The standard HKDF security guarantees only hold if `mbedtls_hkdf()` is
used or if `mbedtls_hkdf_extract()` and `mbedtls_hkdf_expand()` are
called in succession carefully and an equivalent way.

Making `mbedtls_hkdf_extract()` and `mbedtls_hkdf_expand()` static would
prevent any misuse, but doing so would require the TLS 1.3 stack to
break abstraction and bypass the module API.

To reduce the risk of misuse we add warnings to the function
descriptions.
2018-08-14 16:08:38 +01:00
Janos Follath
d0a78e91b3 HKDF: Fix style issue 2018-08-14 16:08:37 +01:00
Thomas Fossati
656864b360 Add an HKDF (RFC 5869) implementation 2018-06-11 13:10:14 +01:00