diff options
Diffstat (limited to 'reference_impl/reference_impl.rs')
| -rw-r--r-- | reference_impl/reference_impl.rs | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/reference_impl/reference_impl.rs b/reference_impl/reference_impl.rs index bb8b511..d97256e 100644 --- a/reference_impl/reference_impl.rs +++ b/reference_impl/reference_impl.rs @@ -12,7 +12,8 @@ const CHUNK_END: u32 = 1 << 1; const PARENT: u32 = 1 << 2; const ROOT: u32 = 1 << 3; const KEYED_HASH: u32 = 1 << 4; -const DERIVE_KEY: u32 = 1 << 5; +const DERIVE_KEY_CONTEXT: u32 = 1 << 5; +const DERIVE_KEY_MATERIAL: u32 = 1 << 6; const IV: [u32; 8] = [ 0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19, @@ -272,11 +273,16 @@ impl Hasher { Self::new_internal(key_words, KEYED_HASH) } - /// Construct a new `Hasher` for the key derivation function. - pub fn new_derive_key(key: &[u8; KEY_LEN]) -> Self { - let mut key_words = [0; 8]; - words_from_litte_endian_bytes(key, &mut key_words); - Self::new_internal(key_words, DERIVE_KEY) + /// Construct a new `Hasher` for the key derivation function. The context + /// string should be hardcoded, globally unique, and application-specific. + pub fn new_derive_key(context: &str) -> Self { + let mut context_hasher = Hasher::new_internal(IV, DERIVE_KEY_CONTEXT); + context_hasher.update(context.as_bytes()); + let mut context_key = [0; KEY_LEN]; + context_hasher.finalize(&mut context_key); + let mut context_key_words = [0; 8]; + words_from_litte_endian_bytes(&context_key, &mut context_key_words); + Self::new_internal(context_key_words, DERIVE_KEY_MATERIAL) } fn push_stack(&mut self, cv: [u32; 8]) { |