diff options
Diffstat (limited to 'openpgp/src/crypto/backend/interface.rs')
| -rw-r--r-- | openpgp/src/crypto/backend/interface.rs | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/openpgp/src/crypto/backend/interface.rs b/openpgp/src/crypto/backend/interface.rs index 864b2714..05e56a8c 100644 --- a/openpgp/src/crypto/backend/interface.rs +++ b/openpgp/src/crypto/backend/interface.rs @@ -4,6 +4,7 @@ use crate::{ Error, Result, crypto::{ + SessionKey, mem::Protected, mpi::{MPI, ProtectedMPI}, }, @@ -11,7 +12,7 @@ use crate::{ }; /// Abstracts over the cryptographic backends. -pub trait Backend: Asymmetric { +pub trait Backend: Asymmetric + Kdf { /// Returns a short, human-readable description of the backend. /// /// This starts with the name of the backend, possibly a version, @@ -121,3 +122,23 @@ mod tests { assert_ne!(secret.as_ref(), public); } } + +/// Key-Derivation-Functions. +pub trait Kdf { + /// HKDF instantiated with SHA256. + /// + /// Used to derive message keys from session keys, and key + /// encapsulating keys from S2K mechanisms. In both cases, using + /// a KDF that includes algorithm information in the given `info` + /// provides key space separation between cipher algorithms and + /// modes. + /// + /// `salt`, if given, SHOULD be 32 bytes of salt matching the + /// digest size of the hash function. If it is not give, 32 zeros + /// are used instead. + /// + /// `okm` must not be larger than 255 * 32 (the size of the hash + /// digest). + fn hkdf_sha256(ikm: &SessionKey, salt: Option<&[u8]>, info: &[u8], + okm: &mut SessionKey) -> Result<()>; +} |