diff --git a/cipher_suites.go b/cipher_suites.go
index e07d742..7631298 100644
--- a/cipher_suites.go
+++ b/cipher_suites.go
@@ -142,7 +142,7 @@ type cipherSuite struct {
 	ka     func(version uint16) keyAgreement
 	// flags is a bitmask of the suite* values, above.
 	flags  int
-	cipher func(key, iv []byte, isRead bool) interface{}
+	cipher func(key, iv []byte, isRead bool) any
 	mac    func(key []byte) hash.Hash
 	aead   func(key, fixedNonce []byte) aead
 }
@@ -401,12 +401,12 @@ func aesgcmPreferred(ciphers []uint16) bool {
 	return false
 }
 
-func cipherRC4(key, iv []byte, isRead bool) interface{} {
+func cipherRC4(key, iv []byte, isRead bool) any {
 	cipher, _ := rc4.NewCipher(key)
 	return cipher
 }
 
-func cipher3DES(key, iv []byte, isRead bool) interface{} {
+func cipher3DES(key, iv []byte, isRead bool) any {
 	block, _ := des.NewTripleDESCipher(key)
 	if isRead {
 		return cipher.NewCBCDecrypter(block, iv)
@@ -414,7 +414,7 @@ func cipher3DES(key, iv []byte, isRead bool) interface{} {
 	return cipher.NewCBCEncrypter(block, iv)
 }
 
-func cipherAES(key, iv []byte, isRead bool) interface{} {
+func cipherAES(key, iv []byte, isRead bool) any {
 	block, _ := aes.NewCipher(key)
 	if isRead {
 		return cipher.NewCBCDecrypter(block, iv)
diff --git a/common.go b/common.go
index d17cac3..fdcebd8 100644
--- a/common.go
+++ b/common.go
@@ -1475,7 +1475,7 @@ func defaultConfig() *Config {
 	return &emptyConfig
 }
 
-func unexpectedMessageError(wanted, got interface{}) error {
+func unexpectedMessageError(wanted, got any) error {
 	return fmt.Errorf("tls: received unexpected handshake message of type %T when waiting for %T", got, wanted)
 }
 
diff --git a/conn.go b/conn.go
index 300e9a2..28ab063 100644
--- a/conn.go
+++ b/conn.go
@@ -163,16 +163,16 @@ func (c *Conn) NetConn() net.Conn {
 type halfConn struct {
 	sync.Mutex
 
-	err     error       // first permanent error
-	version uint16      // protocol version
-	cipher  interface{} // cipher algorithm
+	err     error  // first permanent error
+	version uint16 // protocol version
+	cipher  any    // cipher algorithm
 	mac     hash.Hash
 	seq     [8]byte // 64-bit sequence number
 
 	scratchBuf [13]byte // to avoid allocs; interface method args escape
 
-	nextCipher interface{} // next encryption state
-	nextMac    hash.Hash   // next MAC algorithm
+	nextCipher any       // next encryption state
+	nextMac    hash.Hash // next MAC algorithm
 
 	trafficSecret []byte // current TLS 1.3 traffic secret
 }
@@ -197,7 +197,7 @@ func (hc *halfConn) setErrorLocked(err error) error {
 
 // prepareCipherSpec sets the encryption and MAC states
 // that a subsequent changeCipherSpec will use.
-func (hc *halfConn) prepareCipherSpec(version uint16, cipher interface{}, mac hash.Hash) {
+func (hc *halfConn) prepareCipherSpec(version uint16, cipher any, mac hash.Hash) {
 	hc.version = version
 	hc.nextCipher = cipher
 	hc.nextMac = mac
@@ -935,7 +935,7 @@ func (c *Conn) flush() (int, error) {
 
 // outBufPool pools the record-sized scratch buffers used by writeRecordLocked.
 var outBufPool = sync.Pool{
-	New: func() interface{} {
+	New: func() any {
 		return new([]byte)
 	},
 }
@@ -1011,7 +1011,7 @@ func (c *Conn) writeRecord(typ recordType, data []byte) (int, error) {
 
 // readHandshake reads the next handshake message from
 // the record layer.
-func (c *Conn) readHandshake() (interface{}, error) {
+func (c *Conn) readHandshake() (any, error) {
 	for c.hand.Len() < 4 {
 		if err := c.readRecord(); err != nil {
 			return nil, err
diff --git a/generate_cert.go b/generate_cert.go
index 58fdd02..74509c9 100644
--- a/generate_cert.go
+++ b/generate_cert.go
@@ -37,7 +37,7 @@ var (
 	ed25519Key = flag.Bool("ed25519", false, "Generate an Ed25519 key")
 )
 
-func publicKey(priv interface{}) interface{} {
+func publicKey(priv any) any {
 	switch k := priv.(type) {
 	case *rsa.PrivateKey:
 		return &k.PublicKey
@@ -57,7 +57,7 @@ func main() {
 		log.Fatalf("Missing required --host parameter")
 	}
 
-	var priv interface{}
+	var priv any
 	var err error
 	switch *ecdsaCurve {
 	case "":
diff --git a/handshake_client.go b/handshake_client.go
index c368c6c..7bf0f84 100644
--- a/handshake_client.go
+++ b/handshake_client.go
@@ -660,7 +660,7 @@ func (hs *clientHandshakeState) establishKeys() error {
 
 	clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
 		keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.hello.random, hs.serverHello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
-	var clientCipher, serverCipher interface{}
+	var clientCipher, serverCipher any
 	var clientHash, serverHash hash.Hash
 	if hs.suite.cipher != nil {
 		clientCipher = hs.suite.cipher(clientKey, clientIV, false /* not for reading */)
diff --git a/handshake_client_test.go b/handshake_client_test.go
index 2158f32..0950bb0 100644
--- a/handshake_client_test.go
+++ b/handshake_client_test.go
@@ -134,7 +134,7 @@ type clientTest struct {
 	cert []byte
 	// key, if not nil, contains either a *rsa.PrivateKey, ed25519.PrivateKey or
 	// *ecdsa.PrivateKey which is the private key for the reference server.
-	key interface{}
+	key any
 	// extensions, if not nil, contains a list of extension data to be returned
 	// from the ServerHello. The data should be in standard TLS format with
 	// a 2-byte uint16 type, 2-byte data length, followed by the extension data.
@@ -171,7 +171,7 @@ func (test *clientTest) connFromCommand() (conn *recordingConn, child *exec.Cmd,
 	certPath := tempFile(string(cert))
 	defer os.Remove(certPath)
 
-	var key interface{} = testRSAPrivateKey
+	var key any = testRSAPrivateKey
 	if test.key != nil {
 		key = test.key
 	}
diff --git a/handshake_messages_test.go b/handshake_messages_test.go
index 8821670..2f5d0e4 100644
--- a/handshake_messages_test.go
+++ b/handshake_messages_test.go
@@ -14,7 +14,7 @@ import (
 	"time"
 )
 
-var tests = []interface{}{
+var tests = []any{
 	&clientHelloMsg{},
 	&serverHelloMsg{},
 	&finishedMsg{},
diff --git a/handshake_server.go b/handshake_server.go
index be64248..5db6056 100644
--- a/handshake_server.go
+++ b/handshake_server.go
@@ -681,7 +681,7 @@ func (hs *serverHandshakeState) establishKeys() error {
 	clientMAC, serverMAC, clientKey, serverKey, clientIV, serverIV :=
 		keysFromMasterSecret(c.vers, hs.suite, hs.masterSecret, hs.clientHello.random, hs.hello.random, hs.suite.macLen, hs.suite.keyLen, hs.suite.ivLen)
 
-	var clientCipher, serverCipher interface{}
+	var clientCipher, serverCipher any
 	var clientHash, serverHash hash.Hash
 
 	if hs.suite.aead == nil {
diff --git a/handshake_server_test.go b/handshake_server_test.go
index 5fb2ebb..6d2c405 100644
--- a/handshake_server_test.go
+++ b/handshake_server_test.go
@@ -249,7 +249,7 @@ func TestTLS12OnlyCipherSuites(t *testing.T) {
 	}
 
 	c, s := localPipe(t)
-	replyChan := make(chan interface{})
+	replyChan := make(chan any)
 	go func() {
 		cli := Client(c, testConfig)
 		cli.vers = clientHello.vers
@@ -304,7 +304,7 @@ func TestTLSPointFormats(t *testing.T) {
 			}
 
 			c, s := localPipe(t)
-			replyChan := make(chan interface{})
+			replyChan := make(chan any)
 			go func() {
 				cli := Client(c, testConfig)
 				cli.vers = clientHello.vers
@@ -600,7 +600,7 @@ func (test *serverTest) connFromCommand() (conn *recordingConn, child *exec.Cmd,
 		return nil, nil, err
 	}
 
-	connChan := make(chan interface{}, 1)
+	connChan := make(chan any, 1)
 	go func() {
 		tcpConn, err := l.Accept()
 		if err != nil {