Subpackage exporter

derivepassphrase.exporter ¶

Foreign configuration exporter for derivepassphrase.

get_vault_key ¶

get_vault_key() -> bytes

Automatically determine the vault(1) master key/password.

Query the VAULT_KEY, LOGNAME, USER and USERNAME environment variables, in that order. This is the same algorithm that vault uses.

Returns:

Type	Description
`bytes`	The master key/password. This is generally used as input to a key-derivation function to determine the actual encryption and signing keys for the vault configuration.

Raises:

Type	Description
`KeyError`	We cannot find any of the named environment variables. Please set `VAULT_KEY` manually to the desired value.

get_vault_path ¶

get_vault_path() -> str | bytes | PathLike

Automatically determine the vault(1) configuration path.

Query the VAULT_PATH environment variable, or default to ~/.vault. This is the same algorithm that vault uses. If not absolute, then VAULT_PATH is relative to the home directory.

Returns:

Type	Description
`str \| bytes \| PathLike`	The vault configuration path. Depending on the vault version, this may be a file or a directory.

Raises:

Type	Description
`RuntimeError`	We cannot determine the home directory. Please set `HOME` manually to the correct value.

derivepassphrase.exporter.storeroom ¶

Exporter for the vault “storeroom” configuration format.

The “storeroom” format is the experimental format used in alpha and beta versions of vault beyond v0.3.0. The configuration is stored as a separate directory, which acts like a hash table (i.e. has named slots) and provides an impure quasi-filesystem interface. Each hash table entry is separately encrypted and authenticated. James Coglan designed this format to avoid concurrent write issues when updating or synchronizing the vault configuration with e.g. a cloud service.

The public interface is the export_storeroom_data function. Multiple non-public functions are additionally documented here for didactical and educational reasons, but they are not part of the module API, are subject to change without notice (including removal), and should not be used or relied on.

KeyPair ¶

Bases: TypedDict

A pair of AES256 keys, one for encryption and one for signing.

Attributes:

Name	Type	Description
`encryption_key`	`bytes`	AES256 key, used for encryption with AES256-CBC (with PKCS#7 padding).
`signing_key`	`bytes`	AES256 key, used for signing with HMAC-SHA256.

encryption_key `instance-attribute` ¶

encryption_key: bytes

signing_key `instance-attribute` ¶

signing_key: bytes

MasterKeys ¶

Bases: TypedDict

A triple of AES256 keys, for encryption, signing and hashing.

Attributes:

Name	Type	Description
`hashing_key`	`bytes`	AES256 key, used for hashing with HMAC-SHA256 to derive a hash table slot for an item.
`encryption_key`	`bytes`	AES256 key, used for encryption with AES256-CBC (with PKCS#7 padding).
`signing_key`	`bytes`	AES256 key, used for signing with HMAC-SHA256.

hashing_key `instance-attribute` ¶

hashing_key: bytes

encryption_key `instance-attribute` ¶

encryption_key: bytes

signing_key `instance-attribute` ¶

signing_key: bytes

derive_master_keys_keys ¶

derive_master_keys_keys(
    password: str | bytes, iterations: int
) -> KeyPair

Derive encryption and signing keys for the master keys data.

The master password is run through a key derivation function to obtain a 64-byte string, which is then split to yield two 32-byte keys. The key derivation function is PBKDF2, using HMAC-SHA1 and salted with the storeroom master keys UUID.

Parameters:

Name	Type	Description	Default
`password`	`str \| bytes`	A master password for the storeroom instance. Usually read from the `VAULT_KEY` environment variable, otherwise defaults to the username.	required
`iterations`	`int`	A count of rounds for the underlying key derivation function. Usually stored as a setting next to the encrypted master keys data.	required

Returns:

Type	Description
`KeyPair`	A 2-tuple of keys, the encryption key and the signing key, to decrypt and verify the master keys data with.

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

decrypt_master_keys_data ¶

decrypt_master_keys_data(
    data: bytes, keys: KeyPair
) -> MasterKeys

Decrypt the master keys data.

The master keys data contains:

a 16-byte IV,
a 96-byte AES256-CBC-encrypted payload, plus 16 further bytes of PKCS7 padding, and
a 32-byte MAC of the preceding 128 bytes.

The decrypted payload itself consists of three 32-byte keys: the hashing, encryption and signing keys, in that order.

The encrypted payload is encrypted with the encryption key, and the MAC is created based on the signing key. As per standard cryptographic procedure, the MAC can be verified before attempting to decrypt the payload.

Because the payload size is both fixed and a multiple of the cipher blocksize, in this case, the PKCS7 padding always is b'\x10' * 16.

Parameters:

Name	Type	Description	Default
`data`	`bytes`	The encrypted master keys data.	required
`keys`	`KeyPair`	The encryption and signing keys for the master keys data. These should have previously been derived via the `derive_master_keys_keys` function.	required

Returns:

Type	Description
`MasterKeys`	The master encryption, signing and hashing keys.

Raises:

Type	Description
`InvalidSignature`	The data does not contain a valid signature under the given key.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

decrypt_session_keys ¶

decrypt_session_keys(
    data: bytes, master_keys: MasterKeys
) -> KeyPair

Decrypt the bucket item’s session keys.

The bucket item’s session keys are single-use keys for encrypting and signing a single item in the storage bucket. The encrypted session key data consists of:

a 16-byte IV,
a 64-byte AES256-CBC-encrypted payload, plus 16 further bytes of PKCS7 padding, and
a 32-byte MAC of the preceding 96 bytes.

The encrypted payload is encrypted with the master encryption key, and the MAC is created with the master signing key. As per standard cryptographic procedure, the MAC can be verified before attempting to decrypt the payload.

Because the payload size is both fixed and a multiple of the cipher blocksize, in this case, the PKCS7 padding always is b'\x10' * 16.

Parameters:

Name	Type	Description	Default
`data`	`bytes`	The encrypted bucket item session key data.	required
`master_keys`	`MasterKeys`	The master keys. Presumably these have previously been obtained via the `decrypt_master_keys_data` function.	required

Returns:

Type	Description
`KeyPair`	The bucket item’s encryption and signing keys.

Raises:

Type	Description
`InvalidSignature`	The data does not contain a valid signature under the given key.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

decrypt_contents ¶

decrypt_contents(
    data: bytes, session_keys: KeyPair
) -> bytes

Decrypt the bucket item’s contents.

The data consists of:

a 16-byte IV,
a variable-sized AES256-CBC-encrypted payload (using PKCS7 padding on the inside), and
a 32-byte MAC of the preceding bytes.

The encrypted payload is encrypted with the bucket item’s session encryption key, and the MAC is created with the bucket item’s session signing key. As per standard cryptographic procedure, the MAC can be verified before attempting to decrypt the payload.

Parameters:

Name	Type	Description	Default
`data`	`bytes`	The encrypted bucket item payload data.	required
`session_keys`	`KeyPair`	The bucket item’s session keys. Presumably these have previously been obtained via the `decrypt_session_keys` function.	required

Returns:

Type	Description
`bytes`	The bucket item’s payload.

Raises:

Type	Description
`InvalidSignature`	The data does not contain a valid signature under the given key.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

decrypt_bucket_item ¶

decrypt_bucket_item(
    bucket_item: bytes, master_keys: MasterKeys
) -> bytes

Decrypt a bucket item.

Parameters:

Name	Type	Description	Default
`bucket_item`	`bytes`	The encrypted bucket item.	required
`master_keys`	`MasterKeys`	The master keys. Presumably these have previously been obtained via the `decrypt_master_keys_data` function.	required

Returns:

Type	Description
`bytes`	The decrypted bucket item.

Raises:

Type	Description
`InvalidSignature`	The data does not contain a valid signature under the given key.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

decrypt_bucket_file ¶

decrypt_bucket_file(
    filename: str,
    master_keys: MasterKeys,
    *,
    root_dir: str | bytes | PathLike = "."
) -> Iterator[bytes]

Decrypt a complete bucket.

Parameters:

Name	Type	Description	Default
`filename`	`str`	The bucket file’s filename.	required
`master_keys`	`MasterKeys`	The master keys. Presumably these have previously been obtained via the `decrypt_master_keys_data` function.	required
`root_dir`	`str \| bytes \| PathLike`	The root directory of the data store. The filename is interpreted relatively to this directory.	`'.'`

Yields:

Type	Description
`bytes`	A decrypted bucket item.

Raises:

Type	Description
`InvalidSignature`	The data does not contain a valid signature under the given key.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

Warning

Non-public function, provided for didactical and educational purposes only. Subject to change without notice, including removal.

export_storeroom_data ¶

export_storeroom_data(
    storeroom_path: str | bytes | PathLike | None = None,
    master_keys_key: str | bytes | None = None,
) -> dict[str, Any]

Export the full configuration stored in the storeroom.

Parameters:

Name	Type	Description	Default
`storeroom_path`	`str \| bytes \| PathLike \| None`	Path to the storeroom; usually `~/.vault`. If not given, then query `exporter.get_vault_path` for the value.	`None`
`master_keys_key`	`str \| bytes \| None`	Encryption key/password for the master keys, usually the username, or passed via the `VAULT_KEY` environment variable. If not given, then query `exporter.get_vault_key` for the value.	`None`

Returns:

Type	Description
`dict[str, Any]`	The full configuration, as stored in the storeroom. This may or may not be a valid configuration according to vault or derivepassphrase.

Raises:

Type	Description
`RuntimeError`	Something went wrong during data collection, e.g. we encountered unsupported or corrupted data in the storeroom.
`JSONDecodeError`	An internal JSON data structure failed to parse from disk. The storeroom is probably corrupted.

derivepassphrase.exporter.vault_native ¶

Exporter for the vault native configuration format (v0.2 or v0.3).

The vault native formats are the configuration formats used by vault v0.2 and v0.3. The configuration is stored as a single encrypted file, which is encrypted and authenticated. v0.2 and v0.3 differ in some details concerning key derivation and expected format of internal structures, so they are not compatible. v0.2 additionally contains cryptographic weaknesses (API misuse of a key derivation function, and a low-entropy method of generating initialization vectors for CBC block encryption mode) and should thus be avoided if possible.

The public interface is the export_vault_native_data function. Multiple non-public classes are additionally documented here for didactical and educational reasons, but they are not part of the module API, are subject to change without notice (including removal), and should not be used or relied on.

VaultNativeConfigParser ¶

VaultNativeConfigParser(
    contents: Buffer, password: str | Buffer
)

Bases: ABC

A base parser for vault’s native configuration format.

Certain details are specific to the respective vault versions, and are abstracted out. This class by itself is not instantiable because of this.

Parameters:

Name	Type	Description	Default
`contents`	`Buffer`	The binary contents of the encrypted configuration file. Note: On disk, these are usually stored in base64-encoded form, not in the “raw” form as needed here.	required
`password`	`str \| Buffer`	The vault master key/master passphrase the file is encrypted with. Must be non-empty. See `exporter.get_vault_key` for details. If this is a text string, then the UTF-8 encoding of the string is used as the binary password.	required

Warning

Non-public class, provided for didactical and educational purposes only. Subject to change without notice, including removal.

call ¶

__call__() -> Any

Return the decrypted and parsed vault configuration.

Raises:

Type	Description
`InvalidSignature`	The encrypted configuration does not contain a valid signature.
`ValueError`	The format is invalid, in a non-cryptographic way. (For example, it contains an unsupported version marker, or unexpected extra contents, or invalid padding.)

VaultNativeV03ConfigParser ¶

VaultNativeV03ConfigParser(*args: Any, **kwargs: Any)

Bases: VaultNativeConfigParser

A parser for vault’s native configuration format (v0.3).

This is the modern, pre-storeroom configuration format.

Warning

Non-public class, provided for didactical and educational purposes only. Subject to change without notice, including removal.

VaultNativeV02ConfigParser ¶

VaultNativeV02ConfigParser(*args: Any, **kwargs: Any)

Bases: VaultNativeConfigParser

A parser for vault’s native configuration format (v0.2).

This is the classic configuration format. Compared to v0.3, it contains an (accidental) API misuse for the generation of the master keys, a low-entropy method of generating initialization vectors for the AES-CBC encryption step, and extra layers of base64 encoding. Because of these significantly weakened confidentiality guarantees, v0.2 configurations should be upgraded to at least v0.3 as soon as possible.

Warning

Non-public class, provided for didactical and educational purposes only. Subject to change without notice, including removal.

export_vault_native_data ¶

export_vault_native_data(
    contents: Buffer | None = None,
    key: str | Buffer | None = None,
    *,
    try_formats: Sequence[str] = ("v0.3", "v0.2")
) -> Any

Export the full configuration stored in vault native format.

Parameters:

Name	Type	Description	Default
`contents`	`Buffer \| None`	The binary encrypted contents of the vault configuration file. If not given, then query `exporter.get_vault_path` for the correct filename and read the contents from there. Note: On disk, these are usually stored in base64-encoded form, not in the “raw” form as needed here.	`None`
`key`	`str \| Buffer \| None`	Encryption key/password for the configuration file, usually the username, or passed via the `VAULT_KEY` environment variable. If not given, then query `exporter.get_vault_key` for the value.	`None`
`try_formats`	`Sequence[str]`	A sequence of formats to try out, in order. Each key must be one of `v0.2` or `v0.3`.	`('v0.3', 'v0.2')`

Returns:

Type	Description
`Any`	The vault configuration, as recorded in the configuration file. This may or may not be a valid configuration according to vault or derivepassphrase.

Raises:

Type	Description
`RuntimeError`	Something went wrong during data collection, e.g. we encountered unsupported or corrupted data in the storeroom.
`JSONDecodeError`	An internal JSON data structure failed to parse from disk. The storeroom is probably corrupted.
`ValueError`	The requested formats to try out are invalid, or the encrypted contents aren’t in any of the attempted configuration formats.

Subpackage exporter

derivepassphrase.exporter ¶

get_vault_key ¶

get_vault_path ¶

derivepassphrase.exporter.storeroom ¶

KeyPair ¶

encryption_key instance-attribute ¶

signing_key instance-attribute ¶

MasterKeys ¶

hashing_key instance-attribute ¶

encryption_key instance-attribute ¶

signing_key instance-attribute ¶

derive_master_keys_keys ¶

decrypt_master_keys_data ¶

decrypt_session_keys ¶

decrypt_contents ¶

decrypt_bucket_item ¶

decrypt_bucket_file ¶

export_storeroom_data ¶

derivepassphrase.exporter.vault_native ¶

VaultNativeConfigParser ¶

__call__ ¶

VaultNativeV03ConfigParser ¶

VaultNativeV02ConfigParser ¶

export_vault_native_data ¶

encryption_key `instance-attribute` ¶

signing_key `instance-attribute` ¶

hashing_key `instance-attribute` ¶

encryption_key `instance-attribute` ¶

signing_key `instance-attribute` ¶

call ¶