diff --git a/block/block.go b/block/block.go
index f5a0f064..db2451e0 100644
--- a/block/block.go
+++ b/block/block.go
@@ -1,12 +1,12 @@
 package block
 
 import (
+	"crypto/sha256"
 	"encoding/base64"
 	"fmt"
 	"time"
 
 	"github.com/renproject/id"
-	"golang.org/x/crypto/sha3"
 )
 
 // Kind defines the different kinds of Block that exist.
@@ -190,7 +190,7 @@ func New(header Header, data Data, prevState State) Block {
 	}
 }
 
-// Hash returns the 256-bit SHA3 Hash of the Header and Data.
+// Hash returns the 256-bit SHA2 Hash of the Header and Data.
 func (block Block) Hash() id.Hash {
 	return block.hash
 }
@@ -243,5 +243,5 @@ var (
 
 // ComputeHash of a block basing on its header, data and previous state.
 func ComputeHash(header Header, data Data, prevState State) id.Hash {
-	return sha3.Sum256([]byte(fmt.Sprintf("BlockHash(Header=%v,Data=%v,PreviousState=%v)", header, data, prevState)))
+	return sha256.Sum256([]byte(fmt.Sprintf("BlockHash(Header=%v,Data=%v,PreviousState=%v)", header, data, prevState)))
 }
diff --git a/go.mod b/go.mod
index ba9fbd7b..6af57b31 100644
--- a/go.mod
+++ b/go.mod
@@ -6,7 +6,7 @@ require (
 	github.com/ethereum/go-ethereum v1.9.5
 	github.com/onsi/ginkgo v1.10.1
 	github.com/onsi/gomega v1.7.0
-	github.com/renproject/id v0.1.0
+	github.com/renproject/id v0.1.1
 	github.com/renproject/phi v0.1.0
 	github.com/sirupsen/logrus v1.4.2
 	golang.org/x/crypto v0.0.0-20190911031432-227b76d455e7
diff --git a/go.sum b/go.sum
index dfb78612..dd814782 100644
--- a/go.sum
+++ b/go.sum
@@ -1,3 +1,4 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/ethereum/go-ethereum v1.9.5 h1:4oxsF+/3N/sTgda9XTVG4r+wMVLsveziSMcK83hPbsk=
 github.com/ethereum/go-ethereum v1.9.5/go.mod h1:PwpWDrCLZrV+tfrhqqF6kPknbISMHaJv9Ln3kPCZLwY=
@@ -14,14 +15,18 @@ github.com/onsi/ginkgo v1.10.1/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+
 github.com/onsi/gomega v1.5.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
 github.com/onsi/gomega v1.7.0 h1:XPnZz8VVBHjVsy1vzJmRwIcSwiUO+JFfrv/xGiigmME=
 github.com/onsi/gomega v1.7.0/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/renproject/id v0.1.0 h1:lq8yzXPechAJlqcFUAukPGL8s9E1HaZM95YgbypoFwQ=
 github.com/renproject/id v0.1.0/go.mod h1:i4OJzgjl4XLcU7nfU9UshX7PaBVpnTk3gEVj8dKa6f8=
+github.com/renproject/id v0.1.1 h1:KaV31Xp7SSlyUs5O0vHIw9rhhzrJ0lTOkQXVgbgyPEU=
+github.com/renproject/id v0.1.1/go.mod h1:i4OJzgjl4XLcU7nfU9UshX7PaBVpnTk3gEVj8dKa6f8=
 github.com/renproject/phi v0.1.0 h1:ZOn7QeDribk/uV46OhQWcTLxyuLg7P+xR1Hfl5cOQuI=
 github.com/renproject/phi v0.1.0/go.mod h1:Hrxx2ONVpfByficRjyRd1trecalYr0lo7Z0akx8UXqg=
 github.com/sirupsen/logrus v1.4.2 h1:SPIRibHv4MatM3XXNO2BJeFLZwZ2LvZgfQ5+UNI2im4=
 github.com/sirupsen/logrus v1.4.2/go.mod h1:tLMulIdttU9McNUspp0xgXVQah82FyeX6MwdIuYE2rE=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190820162420-60c769a6c586/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
diff --git a/process/message.go b/process/message.go
index bc302cd0..a225684e 100644
--- a/process/message.go
+++ b/process/message.go
@@ -2,6 +2,7 @@ package process
 
 import (
 	"crypto/ecdsa"
+	"crypto/sha256"
 	"encoding"
 	"encoding/json"
 	"fmt"
@@ -9,7 +10,6 @@ import (
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/renproject/hyperdrive/block"
 	"github.com/renproject/id"
-	"golang.org/x/crypto/sha3"
 )
 
 type MessageType uint64
@@ -115,7 +115,7 @@ func (propose *Propose) Signatory() id.Signatory {
 }
 
 func (propose *Propose) SigHash() id.Hash {
-	return sha3.Sum256([]byte(propose.String()))
+	return sha256.Sum256([]byte(propose.String()))
 }
 
 func (propose *Propose) Sig() id.Signature {
@@ -173,7 +173,7 @@ func (prevote *Prevote) Signatory() id.Signatory {
 }
 
 func (prevote *Prevote) SigHash() id.Hash {
-	return sha3.Sum256([]byte(prevote.String()))
+	return sha256.Sum256([]byte(prevote.String()))
 }
 
 func (prevote *Prevote) Sig() id.Signature {
@@ -223,7 +223,7 @@ func (precommit *Precommit) Signatory() id.Signatory {
 }
 
 func (precommit *Precommit) SigHash() id.Hash {
-	return sha3.Sum256([]byte(precommit.String()))
+	return sha256.Sum256([]byte(precommit.String()))
 }
 
 func (precommit *Precommit) Sig() id.Signature {
diff --git a/testutil/replica/replica.go b/testutil/replica/replica.go
index 56815995..2866e9ba 100644
--- a/testutil/replica/replica.go
+++ b/testutil/replica/replica.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"crypto/ecdsa"
 	"crypto/rand"
+	"crypto/sha256"
 	"fmt"
 	mrand "math/rand"
 	"sync"
@@ -15,7 +16,6 @@ import (
 	"github.com/renproject/hyperdrive/testutil"
 	"github.com/renproject/id"
 	"github.com/renproject/phi"
-	"golang.org/x/crypto/sha3"
 )
 
 func Contain(list []int, target int) bool {
@@ -117,7 +117,7 @@ func (m MockObserver) DidCommitBlock(height block.Height, shard replica.Shard) {
 	if !ok {
 		panic("DidCommitBlock should be called only when the block has been added to storage")
 	}
-	digest := sha3.Sum256(b.Data())
+	digest := sha256.Sum256(b.Data())
 	blockchain.InsertBlockStatAtHeight(height, digest[:])
 
 	// Insert executed state of the previous height