Merge pull request #1199 from valentinewallace/2021-11-phantom-node

[rust-lightning] / lightning / src / util / crypto.rs

diff --git a/lightning/src/util/crypto.rs b/lightning/src/util/crypto.rs
new file mode 100644 (file)
index 0000000..f8a3f84
--- /dev/null
+++ b/lightning/src/util/crypto.rs
@@ -0,0 +1,38 @@
+use bitcoin::hashes::{Hash, HashEngine};
+use bitcoin::hashes::hmac::{Hmac, HmacEngine};
+use bitcoin::hashes::sha256::Hash as Sha256;
+
+macro_rules! hkdf_extract_expand {
+       ($salt: expr, $ikm: expr) => {{
+               let mut hmac = HmacEngine::<Sha256>::new($salt);
+               hmac.input($ikm);
+               let prk = Hmac::from_engine(hmac).into_inner();
+               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
+               hmac.input(&[1; 1]);
+               let t1 = Hmac::from_engine(hmac).into_inner();
+               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
+               hmac.input(&t1);
+               hmac.input(&[2; 1]);
+               (t1, Hmac::from_engine(hmac).into_inner(), prk)
+       }};
+       ($salt: expr, $ikm: expr, 2) => {{
+               let (k1, k2, _) = hkdf_extract_expand!($salt, $ikm);
+               (k1, k2)
+       }};
+       ($salt: expr, $ikm: expr, 3) => {{
+               let (k1, k2, prk) = hkdf_extract_expand!($salt, $ikm);
+
+               let mut hmac = HmacEngine::<Sha256>::new(&prk[..]);
+               hmac.input(&k2);
+               hmac.input(&[3; 1]);
+               (k1, k2, Hmac::from_engine(hmac).into_inner())
+       }}
+}
+
+pub fn hkdf_extract_expand_twice(salt: &[u8], ikm: &[u8]) -> ([u8; 32], [u8; 32]) {
+       hkdf_extract_expand!(salt, ikm, 2)
+}
+
+pub fn hkdf_extract_expand_thrice(salt: &[u8], ikm: &[u8]) -> ([u8; 32], [u8; 32], [u8; 32]) {
+       hkdf_extract_expand!(salt, ikm, 3)
+}