From e01ba500f8e1aa424d59c5817a69930924083b2d Mon Sep 17 00:00:00 2001
From: Mrityunjay Raj <mr.raj.earth@gmail.com>
Date: Mon, 11 May 2026 17:40:11 +0530
Subject: [PATCH 1/2] legacy: move legacy AES-CTR key classes into
 borg.legacy.crypto, refs #9556

---
 src/borg/crypto/key.py             | 48 ++++--------------------------
 src/borg/legacy/crypto/__init__.py |  0
 src/borg/legacy/crypto/key.py      | 42 ++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 43 deletions(-)
 create mode 100644 src/borg/legacy/crypto/__init__.py
 create mode 100644 src/borg/legacy/crypto/key.py

diff --git a/src/borg/crypto/key.py b/src/borg/crypto/key.py
index 1b8e00044..30044bf92 100644
--- a/src/borg/crypto/key.py
+++ b/src/borg/crypto/key.py
@@ -29,7 +29,7 @@ from ..repoobj import RepoObj
 
 
 from .low_level import AES, bytes_to_int, num_cipher_blocks, hmac_sha256, blake2b_256
-from .low_level import AES256_CTR_HMAC_SHA256, AES256_CTR_BLAKE2b, AES256_OCB, CHACHA20_POLY1305
+from .low_level import AES256_OCB, CHACHA20_POLY1305
 from . import low_level
 
 # workaround for lost passphrase or key in "authenticated" or "authenticated-blake2" mode
@@ -729,40 +729,10 @@ class FlexiKey:
             raise TypeError("Unsupported borg key storage type")
 
 
-class KeyfileKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
-    TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
-    TYPE = KeyType.KEYFILE
-    NAME = "key file"
-    ARG_NAME = "keyfile"
-    STORAGE = KeyBlobStorage.KEYFILE
-    CIPHERSUITE = AES256_CTR_HMAC_SHA256
-
-
-class RepoKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
-    TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
-    TYPE = KeyType.REPO
-    NAME = "repokey"
-    ARG_NAME = "repokey"
-    STORAGE = KeyBlobStorage.REPO
-    CIPHERSUITE = AES256_CTR_HMAC_SHA256
-
-
-class Blake2KeyfileKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
-    TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
-    TYPE = KeyType.BLAKE2KEYFILE
-    NAME = "key file BLAKE2b"
-    ARG_NAME = "keyfile-blake2"
-    STORAGE = KeyBlobStorage.KEYFILE
-    CIPHERSUITE = AES256_CTR_BLAKE2b
-
-
-class Blake2RepoKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
-    TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
-    TYPE = KeyType.BLAKE2REPO
-    NAME = "repokey BLAKE2b"
-    ARG_NAME = "repokey-blake2"
-    STORAGE = KeyBlobStorage.REPO
-    CIPHERSUITE = AES256_CTR_BLAKE2b
+# legacy imports placed after FlexiKey/AESKeyBase/KeyBase so those names are already
+# in the partial module when legacy/crypto/key.py imports them back during circular load
+from ..legacy.crypto.key import KeyfileKey, RepoKey, Blake2KeyfileKey, Blake2RepoKey  # noqa: E402
+from ..legacy.crypto.key import LEGACY_KEY_TYPES  # noqa: E402
 
 
 class AuthenticatedKeyBase(AESKeyBase, FlexiKey):
@@ -1002,14 +972,6 @@ class Blake2CHPORepoKey(ID_BLAKE2b_256, AEADKeyBase, FlexiKey):
     CIPHERSUITE = CHACHA20_POLY1305
 
 
-LEGACY_KEY_TYPES = (
-    # legacy (AES-CTR based) crypto
-    KeyfileKey,
-    RepoKey,
-    Blake2KeyfileKey,
-    Blake2RepoKey,
-)
-
 AVAILABLE_KEY_TYPES = (
     # these are available encryption modes for new repositories
     # not encrypted modes
diff --git a/src/borg/legacy/crypto/__init__.py b/src/borg/legacy/crypto/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/src/borg/legacy/crypto/key.py b/src/borg/legacy/crypto/key.py
new file mode 100644
index 000000000..b9fd954a8
--- /dev/null
+++ b/src/borg/legacy/crypto/key.py
@@ -0,0 +1,42 @@
+from ...constants import *  # NOQA
+from ...crypto.low_level import AES256_CTR_HMAC_SHA256, AES256_CTR_BLAKE2b
+from ...crypto.key import ID_HMAC_SHA_256, ID_BLAKE2b_256, AESKeyBase, FlexiKey
+
+
+class KeyfileKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
+    TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
+    TYPE = KeyType.KEYFILE
+    NAME = "key file"
+    ARG_NAME = "keyfile"
+    STORAGE = KeyBlobStorage.KEYFILE
+    CIPHERSUITE = AES256_CTR_HMAC_SHA256
+
+
+class RepoKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
+    TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
+    TYPE = KeyType.REPO
+    NAME = "repokey"
+    ARG_NAME = "repokey"
+    STORAGE = KeyBlobStorage.REPO
+    CIPHERSUITE = AES256_CTR_HMAC_SHA256
+
+
+class Blake2KeyfileKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
+    TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
+    TYPE = KeyType.BLAKE2KEYFILE
+    NAME = "key file BLAKE2b"
+    ARG_NAME = "keyfile-blake2"
+    STORAGE = KeyBlobStorage.KEYFILE
+    CIPHERSUITE = AES256_CTR_BLAKE2b
+
+
+class Blake2RepoKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
+    TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
+    TYPE = KeyType.BLAKE2REPO
+    NAME = "repokey BLAKE2b"
+    ARG_NAME = "repokey-blake2"
+    STORAGE = KeyBlobStorage.REPO
+    CIPHERSUITE = AES256_CTR_BLAKE2b
+
+
+LEGACY_KEY_TYPES = (KeyfileKey, RepoKey, Blake2KeyfileKey, Blake2RepoKey)

From 0cf9322d78944f735cc7f65666543f076537bf6f Mon Sep 17 00:00:00 2001
From: Mrityunjay Raj <mr.raj.earth@gmail.com>
Date: Mon, 11 May 2026 17:56:53 +0530
Subject: [PATCH 2/2] legacy: fix mypy false positives in key classes caused by
 circular import, refs #9556

---
 src/borg/legacy/crypto/key.py | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/borg/legacy/crypto/key.py b/src/borg/legacy/crypto/key.py
index b9fd954a8..4454015ee 100644
--- a/src/borg/legacy/crypto/key.py
+++ b/src/borg/legacy/crypto/key.py
@@ -3,7 +3,7 @@ from ...crypto.low_level import AES256_CTR_HMAC_SHA256, AES256_CTR_BLAKE2b
 from ...crypto.key import ID_HMAC_SHA_256, ID_BLAKE2b_256, AESKeyBase, FlexiKey
 
 
-class KeyfileKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
+class KeyfileKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):  # type: ignore[misc]
     TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
     TYPE = KeyType.KEYFILE
     NAME = "key file"
@@ -12,7 +12,7 @@ class KeyfileKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
     CIPHERSUITE = AES256_CTR_HMAC_SHA256
 
 
-class RepoKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
+class RepoKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):  # type: ignore[misc]
     TYPES_ACCEPTABLE = {KeyType.KEYFILE, KeyType.REPO, KeyType.PASSPHRASE}
     TYPE = KeyType.REPO
     NAME = "repokey"
@@ -21,7 +21,7 @@ class RepoKey(ID_HMAC_SHA_256, AESKeyBase, FlexiKey):
     CIPHERSUITE = AES256_CTR_HMAC_SHA256
 
 
-class Blake2KeyfileKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
+class Blake2KeyfileKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):  # type: ignore[misc]
     TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
     TYPE = KeyType.BLAKE2KEYFILE
     NAME = "key file BLAKE2b"
@@ -30,7 +30,7 @@ class Blake2KeyfileKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
     CIPHERSUITE = AES256_CTR_BLAKE2b
 
 
-class Blake2RepoKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):
+class Blake2RepoKey(ID_BLAKE2b_256, AESKeyBase, FlexiKey):  # type: ignore[misc]
     TYPES_ACCEPTABLE = {KeyType.BLAKE2KEYFILE, KeyType.BLAKE2REPO}
     TYPE = KeyType.BLAKE2REPO
     NAME = "repokey BLAKE2b"