diff --git a/eth.nimble b/eth.nimble
index ea596ce2..96d1e5ff 100644
--- a/eth.nimble
+++ b/eth.nimble
@@ -21,7 +21,8 @@ requires "nim >= 2.0.10",
          "unittest2",
          "results",
          "minilru",
-         "snappy"
+         "snappy",
+         "constantine"
 
 let nimc = getEnv("NIMC", "nim") # Which nim compiler to use
 let lang = getEnv("NIMLANG", "c") # Which backend (c/cpp/js)
diff --git a/eth/common/hashes.nim b/eth/common/hashes.nim
index 0575ab68..e796ac61 100644
--- a/eth/common/hashes.nim
+++ b/eth/common/hashes.nim
@@ -14,11 +14,12 @@
 ## Its usage was limited to ethash, the proof-of-work algorithm that has been
 ## replaced with proof-of-stake.
 
-import std/[typetraits, hashes], nimcrypto/keccak, ./base, stew/assign2
+import std/[typetraits, hashes], ./base, stew/assign2, constantine/hashes/h_keccak, nimcrypto/keccak
 
-export hashes, keccak.update, keccak.finish
+export hashes, keccak.update, keccak.finish, h_keccak
 
 type
+  KECCACK256* = h_keccak.KeccakContext[256, 0x01]
   Hash32* = distinct Bytes32
     ## https://github.com/ethereum/execution-specs/blob/51fac24740e662844446439ceeb96a460aae0ba0/src/ethereum/crypto/hash.py#L19
   Root* = Hash32
@@ -91,14 +92,19 @@ const
     ## of an empty MPT trie
 
 func keccak256*(input: openArray[byte]): Hash32 {.noinit.} =
-  var ctx: keccak.keccak256
+  var
+    ctx: KECCACK256
+    buff: array[32, byte]
   ctx.update(input)
-  ctx.finish().to(Hash32)
+  ctx.finish(buff)
+  Hash32(buff)
 
 func keccak256*(input: openArray[char]): Hash32 {.noinit.} =
   keccak256(input.toOpenArrayByte(0, input.high))
 
 template withKeccak256*(body: untyped): Hash32 =
-  var h {.inject.}: keccak.keccak256
+  var h {.inject.}: KECCACK256
   body
-  h.finish().to(Hash32)
+  var buff: array[32, byte]
+  h.finish(buff)
+  Hash32(buff)
diff --git a/eth/keyfile/keyfile.nim b/eth/keyfile/keyfile.nim
index bbe2b55b..118bf922 100644
--- a/eth/keyfile/keyfile.nim
+++ b/eth/keyfile/keyfile.nim
@@ -186,7 +186,7 @@ proc deriveKey(password: string,
       discard ctx.pbkdf2(password, salt, c, output)
       ok(output)
     of HashSHA3_256:
-      var ctx: HMAC[sha3_256]
+      var ctx: HMAC[keccak.sha3_256]
       discard ctx.pbkdf2(password, salt, c, output)
       ok(output)
     of HashSHA3_384:
@@ -334,7 +334,7 @@ proc createKeyFileJson*(seckey: PrivateKey,
 
     ciphertext = ? encryptKey(seckey, cryptkind, dkey, iv)
 
-  var ctx: keccak256
+  var ctx: keccak.keccak256
   ctx.init()
   ctx.update(toOpenArray(dkey, 16, 31))
   ctx.update(ciphertext)
@@ -432,7 +432,7 @@ proc decodeScryptParams(params: JsonNode): KfResult[ScryptParams] =
   result = ok(p)
 
 func decryptPrivateKey(crypto: Crypto, dkey: DKey): KfResult[PrivateKey] =
-  var ctx: keccak256
+  var ctx: keccak.keccak256
   ctx.init()
   ctx.update(toOpenArray(dkey, 16, 31))
   ctx.update(crypto.cipher.text)
diff --git a/eth/rlp/hash_writer.nim b/eth/rlp/hash_writer.nim
index 1728434a..644ee7e4 100644
--- a/eth/rlp/hash_writer.nim
+++ b/eth/rlp/hash_writer.nim
@@ -8,7 +8,7 @@
 import nimcrypto/keccak, ./priv/defs, utils, ../common/hashes, length_writer
 
 type RlpHashWriter* = object
-  keccak: keccak.keccak256
+  keccak: KECCACK256
   lengths*: seq[int]
   wrapLengths*: seq[int]
   listCount: int
@@ -97,7 +97,9 @@ func reInit*(self: var RlpHashWriter, tracker: var RlpLengthTracker) =
   self.wrapLengths = move(tracker.wrapLengths)
 
 template finish*(self: var RlpHashWriter): Hash32 =
-  self.keccak.finish.to(Hash32)
+  var buff: array[32, byte]
+  self.keccak.finish(buff)
+  Hash32(buff)
 
 func clear*(self: var RlpHashWriter) =
   # Prepare writer for reuse