snapshot of https://github.com/ory/kratos.git (master, 2026-09-15; blobs > 131072B omitted)

cipher/aes.go

@@ -0,0 +1,84 @@
+// Copyright © 2023 Ory Corp
+// SPDX-License-Identifier: Apache-2.0
+
+package cipher
+
+import (
+	"context"
+	"crypto/aes"
+	stdcipher "crypto/cipher"
+	"encoding/hex"
+
+	"github.com/pkg/errors"
+
+	"github.com/ory/herodot"
+)
+
+type AES struct {
+	c SecretsProvider
+}
+
+func NewCryptAES(c SecretsProvider) *AES {
+	return &AES{c: c}
+}
+
+// aesGCM returns an AES-256-GCM AEAD that generates a random nonce internally
+// and prepends it to the ciphertext (nonce | ciphertext | tag).
+func aesGCM(key *[32]byte) (stdcipher.AEAD, error) {
+	block, err := aes.NewCipher(key[:])
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+	gcm, err := stdcipher.NewGCMWithRandomNonce(block)
+	if err != nil {
+		return nil, errors.WithStack(err)
+	}
+	return gcm, nil
+}
+
+// Encrypt returns the AES-256-GCM encryption of plaintext.
+func (a *AES) Encrypt(ctx context.Context, message []byte) (string, error) {
+	if len(message) == 0 {
+		return "", nil
+	}
+
+	if len(a.c.SecretsCipher(ctx)) == 0 {
+		return "", errors.WithStack(herodot.ErrMisconfiguration().WithReason("Unable to encrypt message because no cipher secrets were configured."))
+	}
+
+	gcm, err := aesGCM(&a.c.SecretsCipher(ctx)[0])
+	if err != nil {
+		return "", errors.WithStack(herodot.ErrForbidden().WithWrap(err))
+	}
+
+	return hex.EncodeToString(gcm.Seal(nil, nil, message, nil)), nil
+}
+
+// Decrypt returns the decrypted AES data.
+func (a *AES) Decrypt(ctx context.Context, ciphertext string) ([]byte, error) {
+	if len(ciphertext) == 0 {
+		return nil, nil
+	}
+
+	secrets := a.c.SecretsCipher(ctx)
+	if len(secrets) == 0 {
+		return nil, errors.WithStack(herodot.ErrMisconfiguration().WithReason("Unable to decipher the encrypted message because no AES secrets were configured."))
+	}
+
+	decode, err := hex.DecodeString(ciphertext)
+	if err != nil {
+		return nil, errors.WithStack(herodot.ErrBadRequest().WithWrap(err))
+	}
+
+	for i := range secrets {
+		gcm, err := aesGCM(&secrets[i])
+		if err != nil {
+			continue
+		}
+		if plaintext, err := gcm.Open(nil, nil, decode, nil); err == nil {
+			return plaintext, nil
+		}
+	}
+
+	return nil, errors.WithStack(herodot.ErrForbidden().WithReason("Unable to decipher the encrypted message."))
+}