1 files changed, 28 insertions, 0 deletions
diff --git a/ext/crypto/lib.rs b/ext/crypto/lib.rs
index f2df7ba10..319f26c22 100644
--- a/ext/crypto/lib.rs
+++ b/ext/crypto/lib.rs
@@ -26,6 +26,7 @@ use rand::thread_rng;
 use rand::Rng;
 use rand::SeedableRng;
 use ring::digest;
+use ring::hkdf;
 use ring::hmac::Algorithm as HmacAlgorithm;
 use ring::hmac::Key as HmacKey;
 use ring::pbkdf2;
@@ -56,6 +57,7 @@ mod key;
 use crate::key::Algorithm;
 use crate::key::CryptoHash;
 use crate::key::CryptoNamedCurve;
+use crate::key::HkdfOutput;
 
 // Allowlist for RSA public exponents.
 lazy_static! {
@@ -558,6 +560,7 @@ pub struct DeriveKeyArg {
   hash: Option<CryptoHash>,
   length: usize,
   iterations: Option<u32>,
+  info: Option<ZeroCopyBuf>,
 }
 
 pub async fn op_crypto_derive_bits(
@@ -589,6 +592,31 @@ pub async fn op_crypto_derive_bits(
       pbkdf2::derive(algorithm, iterations, salt, &secret, &mut out);
       Ok(out.into())
     }
+    Algorithm::Hkdf => {
+      let algorithm = match args.hash.ok_or_else(not_supported)? {
+        CryptoHash::Sha1 => hkdf::HKDF_SHA1_FOR_LEGACY_USE_ONLY,
+        CryptoHash::Sha256 => hkdf::HKDF_SHA256,
+        CryptoHash::Sha384 => hkdf::HKDF_SHA384,
+        CryptoHash::Sha512 => hkdf::HKDF_SHA512,
+      };
+
+      let info = args
+        .info
+        .ok_or_else(|| type_error("Missing argument info".to_string()))?;
+      // IKM
+      let secret = args.key.data;
+      // L
+      let length = args.length / 8;
+
+      let salt = hkdf::Salt::new(algorithm, salt);
+      let prk = salt.extract(&secret);
+      let info = &[&*info];
+      let okm = prk.expand(info, HkdfOutput(length))?;
+      let mut r = vec![0u8; length];
+      okm.fill(&mut r)?;
+
+      Ok(r.into())
+    }
     _ => Err(type_error("Unsupported algorithm".to_string())),
   }
 }