crypto: add support for KMS key versions

This commit adds support for KMS master key versions.
Now, MinIO stores any key version information returned by the
KMS as part of the object metadata. The key version identifies
a particular master key within a master key ring. When encrypting/
generating a DEK, MinIO has to remember the key version - similar to
the key name. When decrypting a DEK, MinIO sends the key version to
the KMS such that the KMS can identify the exact key version that
should be used to decrypt the object.

Existing objects don't have a key version. Hence, this field will
be empty.

Signed-off-by: Andreas Auernhammer <github@aead.dev>

cmd/bucket-metadata.go

@@ -555,7 +555,7 @@ func encryptBucketMetadata(ctx context.Context, bucket string, input []byte, kms
 	outbuf := bytes.NewBuffer(nil)
 	objectKey := crypto.GenerateKey(key.Plaintext, rand.Reader)
 	sealedKey := objectKey.Seal(key.Plaintext, crypto.GenerateIV(rand.Reader), crypto.S3.String(), bucket, "")
-	crypto.S3.CreateMetadata(metadata, key.KeyID, key.Ciphertext, sealedKey)
+	crypto.S3.CreateMetadata(metadata, key, sealedKey)
 	_, err = sio.Encrypt(outbuf, bytes.NewBuffer(input), sio.Config{Key: objectKey[:], MinVersion: sio.Version20, CipherSuites: fips.DARECiphers()})
 	if err != nil {
 		return output, metabytes, err

cmd/encryption-v1.go

@@ -293,7 +293,7 @@ func rotateKey(ctx context.Context, oldKey []byte, newKeyID string, newKey []byt
 			return err
 		}
 		sealedKey = objectKey.Seal(newKey.Plaintext, crypto.GenerateIV(rand.Reader), crypto.S3.String(), bucket, object)
-		crypto.S3.CreateMetadata(metadata, newKey.KeyID, newKey.Ciphertext, sealedKey)
+		crypto.S3.CreateMetadata(metadata, newKey, sealedKey)
 		return nil
 	case crypto.S3KMS:
 		if GlobalKMS == nil {
@@ -333,7 +333,7 @@ func rotateKey(ctx context.Context, oldKey []byte, newKeyID string, newKey []byt
 		}
 
 		sealedKey := objectKey.Seal(newKey.Plaintext, crypto.GenerateIV(rand.Reader), crypto.S3KMS.String(), bucket, object)
-		crypto.S3KMS.CreateMetadata(metadata, newKey.KeyID, newKey.Ciphertext, sealedKey, cryptoCtx)
+		crypto.S3KMS.CreateMetadata(metadata, newKey, sealedKey, cryptoCtx)
 		return nil
 	case crypto.SSEC:
 		sealedKey, err := crypto.SSEC.ParseMetadata(metadata)
@@ -376,7 +376,7 @@ func newEncryptMetadata(ctx context.Context, kind crypto.Type, keyID string, key
 
 		objectKey := crypto.GenerateKey(key.Plaintext, rand.Reader)
 		sealedKey = objectKey.Seal(key.Plaintext, crypto.GenerateIV(rand.Reader), crypto.S3.String(), bucket, object)
-		crypto.S3.CreateMetadata(metadata, key.KeyID, key.Ciphertext, sealedKey)
+		crypto.S3.CreateMetadata(metadata, key, sealedKey)
 		return objectKey, nil
 	case crypto.S3KMS:
 		if GlobalKMS == nil {
@@ -409,7 +409,7 @@ func newEncryptMetadata(ctx context.Context, kind crypto.Type, keyID string, key
 
 		objectKey := crypto.GenerateKey(key.Plaintext, rand.Reader)
 		sealedKey = objectKey.Seal(key.Plaintext, crypto.GenerateIV(rand.Reader), crypto.S3KMS.String(), bucket, object)
-		crypto.S3KMS.CreateMetadata(metadata, key.KeyID, key.Ciphertext, sealedKey, cryptoCtx)
+		crypto.S3KMS.CreateMetadata(metadata, key, sealedKey, cryptoCtx)
 		return objectKey, nil
 	case crypto.SSEC:
 		objectKey := crypto.GenerateKey(key, rand.Reader)

cmd/kms-handlers.go

@@ -280,6 +280,7 @@ func (a kmsAPIHandlers) KMSKeyStatusHandler(w http.ResponseWriter, r *http.Reque
 	// 2. Verify that we can indeed decrypt the (encrypted) key
 	decryptedKey, err := GlobalKMS.Decrypt(ctx, &kms.DecryptRequest{
 		Name:           key.KeyID,
+		Version:        key.Version,
 		Ciphertext:     key.Ciphertext,
 		AssociatedData: kmsContext,
 	})

cmd/metacache-stream.go

@@ -758,7 +758,7 @@ func (r *metacacheReader) Close() error {
 	return nil
 }
 
-// metacacheBlockWriter collects blocks and provides a callaback to store them.
+// metacacheBlockWriter collects blocks and provides a callback to store them.
 type metacacheBlockWriter struct {
 	wg           sync.WaitGroup
 	streamErr    error

go.mod

@@ -56,7 +56,7 @@ require (
 	github.com/minio/dnscache v0.1.1
 	github.com/minio/dperf v0.6.3
 	github.com/minio/highwayhash v1.0.3
-	github.com/minio/kms-go/kes v0.3.1
+	github.com/minio/kms-go/kes v0.3.2-0.20250505160844-240efef6bb74
 	github.com/minio/kms-go/kms v0.5.1-0.20250225090116-4e64ce8d0f35
 	github.com/minio/madmin-go/v3 v3.0.109
 	github.com/minio/minio-go/v7 v7.0.91

go.sum

@@ -436,8 +436,8 @@ github.com/minio/filepath v1.0.0/go.mod h1:/nRZA2ldl5z6jT9/KQuvZcQlxZIMQoFFQPvEX
 github.com/minio/highwayhash v1.0.2/go.mod h1:BQskDq+xkJ12lmlUUi7U0M5Swg3EWR+dLTk+kldvVxY=
 github.com/minio/highwayhash v1.0.3 h1:kbnuUMoHYyVl7szWjSxJnxw11k2U709jqFPPmIUyD6Q=
 github.com/minio/highwayhash v1.0.3/go.mod h1:GGYsuwP/fPD6Y9hMiXuapVvlIUEhFhMTh0rxU3ik1LQ=
-github.com/minio/kms-go/kes v0.3.1 h1:K3sPFAvFbJx33XlCTUBnQo8JRmSZyDvT6T2/MQ2iC3A=
-github.com/minio/kms-go/kes v0.3.1/go.mod h1:Q9Ct0KUAuN9dH0hSVa0eva45Jg99cahbZpPxeqR9rOQ=
+github.com/minio/kms-go/kes v0.3.2-0.20250505160844-240efef6bb74 h1:iUY0/rQ66zmowoB94yGBTk3I2ljOoD5jSIKwkhxkwe4=
+github.com/minio/kms-go/kes v0.3.2-0.20250505160844-240efef6bb74/go.mod h1:Q9Ct0KUAuN9dH0hSVa0eva45Jg99cahbZpPxeqR9rOQ=
 github.com/minio/kms-go/kms v0.5.1-0.20250225090116-4e64ce8d0f35 h1:ISNz42SPD+heeHhpl9bwMRRusPTCsbYKd1YoED265E0=
 github.com/minio/kms-go/kms v0.5.1-0.20250225090116-4e64ce8d0f35/go.mod h1:JFQu2srrnWxMn6KcwS5347oTwNKW7nkewgBlrodjF9k=
 github.com/minio/madmin-go/v3 v3.0.109 h1:hRHlJ6yaIB3tlIj5mz9L9mGcyLC37S9qL1WtFrRtyQ0=

internal/config/crypto.go

@@ -92,6 +92,7 @@ func Encrypt(k *kms.KMS, plaintext io.Reader, ctx kms.Context) (io.Reader, error
 	json := jsoniter.ConfigCompatibleWithStandardLibrary
 	metadata, err := json.Marshal(encryptedObject{
 		KeyID:     key.KeyID,
+		Version:   key.Version,
 		KMSKey:    key.Ciphertext,
 		Algorithm: algorithm,
 		Nonce:     nonce,
@@ -151,6 +152,7 @@ func Decrypt(k *kms.KMS, ciphertext io.Reader, associatedData kms.Context) (io.R
 
 	key, err := k.Decrypt(context.TODO(), &kms.DecryptRequest{
 		Name:           metadata.KeyID,
+		Version:        metadata.Version,
 		Ciphertext:     metadata.KMSKey,
 		AssociatedData: associatedData,
 	})
@@ -168,8 +170,9 @@ func Decrypt(k *kms.KMS, ciphertext io.Reader, associatedData kms.Context) (io.R
 }
 
 type encryptedObject struct {
-	KeyID  string `json:"keyid"`
-	KMSKey []byte `json:"kmskey"`
+	KeyID   string `json:"keyid"`
+	Version string `json:"version"`
+	KMSKey  []byte `json:"kmskey"`
 
 	Algorithm sio.Algorithm `json:"algorithm"`
 	Nonce     []byte        `json:"nonce"`

internal/crypto/metadata.go

@@ -48,6 +48,12 @@ const (
 	// the KMS.
 	MetaDataEncryptionKey = "X-Minio-Internal-Server-Side-Encryption-S3-Kms-Sealed-Key"
 
+	// MetaKeyVersion is the version of the KMS master key used to generate/encrypt
+	// the data encryption key (DEK). When a MinKMS master key is "rotated", it
+	// adds another key version. MinIO has to remember which key version has been
+	// used to encrypt an object.
+	MetaKeyVersion = "X-Minio-Internal-Server-Side-Encryption-S3-Kms-Key-Version"
+
 	// MetaSsecCRC is the encrypted checksum of the SSE-C encrypted object.
 	MetaSsecCRC = "X-Minio-Replication-Ssec-Crc"
 
@@ -108,6 +114,7 @@ func RemoveInternalEntries(metadata map[string]string) {
 	delete(metadata, MetaSealedKeyS3)
 	delete(metadata, MetaSealedKeyKMS)
 	delete(metadata, MetaKeyID)
+	delete(metadata, MetaKeyVersion)
 	delete(metadata, MetaDataEncryptionKey)
 	delete(metadata, MetaSsecCRC)
 }
@@ -150,6 +157,9 @@ func IsEncrypted(metadata map[string]string) (Type, bool) {
 	if _, ok := metadata[MetaKeyID]; ok {
 		return nil, true
 	}
+	if _, ok := metadata[MetaKeyVersion]; ok {
+		return nil, true
+	}
 	if _, ok := metadata[MetaDataEncryptionKey]; ok {
 		return nil, true
 	}

internal/crypto/metadata_test.go

@@ -23,6 +23,7 @@ import (
 	"encoding/hex"
 	"testing"
 
+	"github.com/minio/minio/internal/kms"
 	"github.com/minio/minio/internal/logger"
 )
 
@@ -306,7 +307,7 @@ var s3CreateMetadataTests = []struct {
 	SealedDataKey []byte
 	SealedKey     SealedKey
 }{
-	{KeyID: "", SealedDataKey: nil, SealedKey: SealedKey{Algorithm: SealAlgorithm}},
+	{KeyID: "foo", SealedDataKey: make([]byte, 32), SealedKey: SealedKey{Algorithm: SealAlgorithm}},
 	{KeyID: "my-minio-key", SealedDataKey: make([]byte, 48), SealedKey: SealedKey{Algorithm: SealAlgorithm}},
 	{KeyID: "cafebabe", SealedDataKey: make([]byte, 48), SealedKey: SealedKey{Algorithm: SealAlgorithm}},
 	{KeyID: "deadbeef", SealedDataKey: make([]byte, 32), SealedKey: SealedKey{IV: [32]byte{0xf7}, Key: [64]byte{0xea}, Algorithm: SealAlgorithm}},
@@ -316,7 +317,7 @@ func TestS3CreateMetadata(t *testing.T) {
 	defer func(l bool) { logger.DisableLog = l }(logger.DisableLog)
 	logger.DisableLog = true
 	for i, test := range s3CreateMetadataTests {
-		metadata := S3.CreateMetadata(nil, test.KeyID, test.SealedDataKey, test.SealedKey)
+		metadata := S3.CreateMetadata(nil, kms.DEK{KeyID: test.KeyID, Ciphertext: test.SealedDataKey}, test.SealedKey)
 		keyID, kmsKey, sealedKey, err := S3.ParseMetadata(metadata)
 		if err != nil {
 			t.Errorf("Test %d: failed to parse metadata: %v", i, err)
@@ -344,7 +345,7 @@ func TestS3CreateMetadata(t *testing.T) {
 			t.Errorf("Expected '%s' panic for invalid seal algorithm but got '%s'", logger.ErrCritical, err)
 		}
 	}()
-	_ = S3.CreateMetadata(nil, "", []byte{}, SealedKey{Algorithm: InsecureSealAlgorithm})
+	_ = S3.CreateMetadata(nil, kms.DEK{}, SealedKey{Algorithm: InsecureSealAlgorithm})
 }
 
 var ssecCreateMetadataTests = []struct {

internal/crypto/sse-kms.go

@@ -136,20 +136,15 @@ func (s3 ssekms) UnsealObjectKey(k *kms.KMS, metadata map[string]string, bucket,
 // the modified metadata. If the keyID and the kmsKey is not empty it encodes
 // both into the metadata as well. It allocates a new metadata map if metadata
 // is nil.
-func (ssekms) CreateMetadata(metadata map[string]string, keyID string, kmsKey []byte, sealedKey SealedKey, ctx kms.Context) map[string]string {
+func (ssekms) CreateMetadata(metadata map[string]string, dek kms.DEK, sealedKey SealedKey, ctx kms.Context) map[string]string {
 	if sealedKey.Algorithm != SealAlgorithm {
 		logger.CriticalIf(context.Background(), Errorf("The seal algorithm '%s' is invalid for SSE-S3", sealedKey.Algorithm))
 	}
-
-	// There are two possibilities:
-	// - We use a KMS -> There must be non-empty key ID and a KMS data key.
-	// - We use a K/V -> There must be no key ID and no KMS data key.
-	// Otherwise, the caller has passed an invalid argument combination.
-	if keyID == "" && len(kmsKey) != 0 {
-		logger.CriticalIf(context.Background(), errors.New("The key ID must not be empty if a KMS data key is present"))
+	if dek.KeyID == "" {
+		logger.CriticalIf(context.Background(), errors.New("The key ID must not be empty"))
 	}
-	if keyID != "" && len(kmsKey) == 0 {
-		logger.CriticalIf(context.Background(), errors.New("The KMS data key must not be empty if a key ID is present"))
+	if len(dek.Ciphertext) == 0 {
+		logger.CriticalIf(context.Background(), errors.New("The DEK must not be empty"))
 	}
 
 	if metadata == nil {
@@ -159,13 +154,18 @@ func (ssekms) CreateMetadata(metadata map[string]string, keyID string, kmsKey []
 	metadata[MetaAlgorithm] = sealedKey.Algorithm
 	metadata[MetaIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
 	metadata[MetaSealedKeyKMS] = base64.StdEncoding.EncodeToString(sealedKey.Key[:])
+	metadata[MetaKeyID] = dek.KeyID
+	metadata[MetaDataEncryptionKey] = base64.StdEncoding.EncodeToString(dek.Ciphertext)
+
 	if len(ctx) > 0 {
-		b, _ := ctx.MarshalText()
+		b, err := ctx.MarshalText()
+		if err != nil {
+			logger.CriticalIf(context.Background(), Errorf("crypto: failed to marshal KMS context: %v", err))
+		}
 		metadata[MetaContext] = base64.StdEncoding.EncodeToString(b)
 	}
-	if len(kmsKey) > 0 && keyID != "" { // We use a KMS -> Store key ID and sealed KMS data key.
-		metadata[MetaKeyID] = keyID
-		metadata[MetaDataEncryptionKey] = base64.StdEncoding.EncodeToString(kmsKey)
+	if dek.Version != "" {
+		metadata[MetaKeyVersion] = dek.Version
 	}
 	return metadata
 }

internal/crypto/sse-s3.go

@@ -119,20 +119,15 @@ func (s3 sses3) UnsealObjectKeys(ctx context.Context, k *kms.KMS, metadata []map
 // the modified metadata. If the keyID and the kmsKey is not empty it encodes
 // both into the metadata as well. It allocates a new metadata map if metadata
 // is nil.
-func (sses3) CreateMetadata(metadata map[string]string, keyID string, kmsKey []byte, sealedKey SealedKey) map[string]string {
+func (sses3) CreateMetadata(metadata map[string]string, dek kms.DEK, sealedKey SealedKey) map[string]string {
 	if sealedKey.Algorithm != SealAlgorithm {
 		logger.CriticalIf(context.Background(), Errorf("The seal algorithm '%s' is invalid for SSE-S3", sealedKey.Algorithm))
 	}
-
-	// There are two possibilities:
-	// - We use a KMS -> There must be non-empty key ID and a KMS data key.
-	// - We use a K/V -> There must be no key ID and no KMS data key.
-	// Otherwise, the caller has passed an invalid argument combination.
-	if keyID == "" && len(kmsKey) != 0 {
-		logger.CriticalIf(context.Background(), errors.New("The key ID must not be empty if a KMS data key is present"))
+	if dek.KeyID == "" {
+		logger.CriticalIf(context.Background(), errors.New("The key ID must not be empty"))
 	}
-	if keyID != "" && len(kmsKey) == 0 {
-		logger.CriticalIf(context.Background(), errors.New("The KMS data key must not be empty if a key ID is present"))
+	if len(dek.Ciphertext) == 0 {
+		logger.CriticalIf(context.Background(), errors.New("The DEK must not be empty"))
 	}
 
 	if metadata == nil {
@@ -142,9 +137,10 @@ func (sses3) CreateMetadata(metadata map[string]string, keyID string, kmsKey []b
 	metadata[MetaAlgorithm] = sealedKey.Algorithm
 	metadata[MetaIV] = base64.StdEncoding.EncodeToString(sealedKey.IV[:])
 	metadata[MetaSealedKeyS3] = base64.StdEncoding.EncodeToString(sealedKey.Key[:])
-	if len(kmsKey) > 0 && keyID != "" { // We use a KMS -> Store key ID and sealed KMS data key.
-		metadata[MetaKeyID] = keyID
-		metadata[MetaDataEncryptionKey] = base64.StdEncoding.EncodeToString(kmsKey)
+	metadata[MetaKeyID] = dek.KeyID
+	metadata[MetaDataEncryptionKey] = base64.StdEncoding.EncodeToString(dek.Ciphertext)
+	if dek.Version != "" {
+		metadata[MetaKeyVersion] = dek.Version
 	}
 	return metadata
 }

internal/kms/conn.go

@@ -19,11 +19,8 @@ package kms
 
 import (
 	"context"
-	"encoding"
-	"encoding/json"
 	"strconv"
 
-	jsoniter "github.com/json-iterator/go"
 	"github.com/minio/madmin-go/v3"
 )
 
@@ -121,47 +118,7 @@ type Status struct {
 // storage.
 type DEK struct {
 	KeyID      string // Name of the master key
-	Version    int    // Version of the master key (MinKMS only)
+	Version    string // Version of the master key
 	Plaintext  []byte // Paintext of the data encryption key
 	Ciphertext []byte // Ciphertext of the data encryption key
 }
-
-var (
-	_ encoding.TextMarshaler   = (*DEK)(nil)
-	_ encoding.TextUnmarshaler = (*DEK)(nil)
-)
-
-// MarshalText encodes the DEK's key ID and ciphertext
-// as JSON.
-func (d DEK) MarshalText() ([]byte, error) {
-	type JSON struct {
-		KeyID      string `json:"keyid"`
-		Version    uint32 `json:"version,omitempty"`
-		Ciphertext []byte `json:"ciphertext"`
-	}
-	return json.Marshal(JSON{
-		KeyID:      d.KeyID,
-		Version:    uint32(d.Version),
-		Ciphertext: d.Ciphertext,
-	})
-}
-
-// UnmarshalText tries to decode text as JSON representation
-// of a DEK and sets DEK's key ID and ciphertext to the
-// decoded values.
-//
-// It sets DEK's plaintext to nil.
-func (d *DEK) UnmarshalText(text []byte) error {
-	type JSON struct {
-		KeyID      string `json:"keyid"`
-		Version    uint32 `json:"version"`
-		Ciphertext []byte `json:"ciphertext"`
-	}
-	var v JSON
-	json := jsoniter.ConfigCompatibleWithStandardLibrary
-	if err := json.Unmarshal(text, &v); err != nil {
-		return err
-	}
-	d.KeyID, d.Version, d.Plaintext, d.Ciphertext = v.KeyID, int(v.Version), nil, v.Ciphertext
-	return nil
-}

internal/kms/dek_test.go

@@ -1,79 +0,0 @@
-// Copyright (c) 2015-2021 MinIO, Inc.
-//
-// This file is part of MinIO Object Storage stack
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-package kms
-
-import (
-	"bytes"
-	"encoding/base64"
-	"testing"
-)
-
-var dekEncodeDecodeTests = []struct {
-	Key DEK
-}{
-	{
-		Key: DEK{},
-	},
-	{
-		Key: DEK{
-			Plaintext:  nil,
-			Ciphertext: mustDecodeB64("eyJhZWFkIjoiQUVTLTI1Ni1HQ00tSE1BQy1TSEEtMjU2IiwiaXYiOiJ3NmhLUFVNZXVtejZ5UlVZL29pTFVBPT0iLCJub25jZSI6IktMSEU3UE1jRGo2N2UweHkiLCJieXRlcyI6Ik1wUkhjQWJaTzZ1Sm5lUGJGcnpKTkxZOG9pdkxwTmlUcTNLZ0hWdWNGYkR2Y0RlbEh1c1lYT29zblJWVTZoSXIifQ=="),
-		},
-	},
-	{
-		Key: DEK{
-			Plaintext:  mustDecodeB64("GM2UvLXp/X8lzqq0mibFC0LayDCGlmTHQhYLj7qAy7Q="),
-			Ciphertext: mustDecodeB64("eyJhZWFkIjoiQUVTLTI1Ni1HQ00tSE1BQy1TSEEtMjU2IiwiaXYiOiJ3NmhLUFVNZXVtejZ5UlVZL29pTFVBPT0iLCJub25jZSI6IktMSEU3UE1jRGo2N2UweHkiLCJieXRlcyI6Ik1wUkhjQWJaTzZ1Sm5lUGJGcnpKTkxZOG9pdkxwTmlUcTNLZ0hWdWNGYkR2Y0RlbEh1c1lYT29zblJWVTZoSXIifQ=="),
-		},
-	},
-	{
-		Key: DEK{
-			Version:    3,
-			Plaintext:  mustDecodeB64("GM2UvLXp/X8lzqq0mibFC0LayDCGlmTHQhYLj7qAy7Q="),
-			Ciphertext: mustDecodeB64("eyJhZWFkIjoiQUVTLTI1Ni1HQ00tSE1BQy1TSEEtMjU2IiwiaXYiOiJ3NmhLUFVNZXVtejZ5UlVZL29pTFVBPT0iLCJub25jZSI6IktMSEU3UE1jRGo2N2UweHkiLCJieXRlcyI6Ik1wUkhjQWJaTzZ1Sm5lUGJGcnpKTkxZOG9pdkxwTmlUcTNLZ0hWdWNGYkR2Y0RlbEh1c1lYT29zblJWVTZoSXIifQ=="),
-		},
-	},
-}
-
-func TestEncodeDecodeDEK(t *testing.T) {
-	for i, test := range dekEncodeDecodeTests {
-		text, err := test.Key.MarshalText()
-		if err != nil {
-			t.Fatalf("Test %d: failed to marshal DEK: %v", i, err)
-		}
-
-		var key DEK
-		if err = key.UnmarshalText(text); err != nil {
-			t.Fatalf("Test %d: failed to unmarshal DEK: %v", i, err)
-		}
-		if key.Plaintext != nil {
-			t.Fatalf("Test %d: unmarshaled DEK contains non-nil plaintext", i)
-		}
-		if !bytes.Equal(key.Ciphertext, test.Key.Ciphertext) {
-			t.Fatalf("Test %d: ciphertext mismatch: got %x - want %x", i, key.Ciphertext, test.Key.Ciphertext)
-		}
-	}
-}
-
-func mustDecodeB64(s string) []byte {
-	b, err := base64.StdEncoding.DecodeString(s)
-	if err != nil {
-		panic(err)
-	}
-	return b
-}

internal/kms/kes.go

@@ -206,6 +206,7 @@ func (c *kesConn) GenerateKey(ctx context.Context, req *GenerateKeyRequest) (DEK
 		KeyID:      name,
 		Plaintext:  dek.Plaintext,
 		Ciphertext: dek.Ciphertext,
+		Version:    dek.Version,
 	}, nil
 }
 
@@ -235,7 +236,7 @@ func (c *kesConn) Decrypt(ctx context.Context, req *DecryptRequest) ([]byte, err
 		return nil, err
 	}
 
-	plaintext, err := c.client.Decrypt(context.Background(), req.Name, req.Ciphertext, aad)
+	plaintext, err := c.client.Decrypt(ctx, req.Name, req.Version, req.Ciphertext, aad)
 	if err != nil {
 		if errors.Is(err, kes.ErrKeyNotFound) {
 			return nil, ErrKeyNotFound

internal/kms/kms.go

@@ -22,6 +22,7 @@ import (
 	"errors"
 	"net/http"
 	"slices"
+	"strconv"
 	"sync/atomic"
 	"time"
 
@@ -90,7 +91,7 @@ type DecryptRequest struct {
 	// Version is the version of the master used for
 	// decryption. If empty, the latest key version
 	// is used.
-	Version int
+	Version string
 
 	// Ciphertext is the encrypted data that gets
 	// decrypted.
@@ -383,7 +384,7 @@ func (c *kmsConn) GenerateKey(ctx context.Context, req *GenerateKeyRequest) (DEK
 
 	return DEK{
 		KeyID:      name,
-		Version:    resp[0].Version,
+		Version:    strconv.Itoa(resp[0].Version),
 		Plaintext:  resp[0].Plaintext,
 		Ciphertext: resp[0].Ciphertext,
 	}, nil
@@ -395,9 +396,17 @@ func (c *kmsConn) Decrypt(ctx context.Context, req *DecryptRequest) ([]byte, err
 		return nil, err
 	}
 
+	version := 1
+	if req.Version != "" {
+		if version, err = strconv.Atoi(req.Version); err != nil {
+			return nil, err
+		}
+	}
+
 	ciphertext, _ := parseCiphertext(req.Ciphertext)
 	resp, err := c.client.Decrypt(ctx, c.enclave, &kms.DecryptRequest{
 		Name:           req.Name,
+		Version:        version,
 		Ciphertext:     ciphertext,
 		AssociatedData: aad,
 	})

internal/kms/secret-key.go

@@ -154,7 +154,6 @@ func (s secretKey) GenerateKey(_ context.Context, req *GenerateKeyRequest) (DEK,
 	ciphertext = append(ciphertext, random...)
 	return DEK{
 		KeyID:      req.Name,
-		Version:    0,
 		Plaintext:  plaintext,
 		Ciphertext: ciphertext,
 	}, nil

internal/kms/stub.go

@@ -103,7 +103,7 @@ func (s StubKMS) GenerateKey(_ context.Context, req *GenerateKeyRequest) (DEK, e
 	}
 	return DEK{
 		KeyID:      req.Name,
-		Version:    0,
+		Version:    "0",
 		Plaintext:  []byte("stubplaincharswhichare32bytelong"),
 		Ciphertext: []byte("stubplaincharswhichare32bytelong"),
 	}, nil