OXIESEC PANEL

Name	Size	Modified	Perms
📁 ..	-	04/29/2025 04:07:53 PM	rwxr-xr-x
📄 __init__.py	336 bytes	10/17/2019 01:00:23 PM	rw-r--r--
📁 __pycache__	-	04/29/2025 04:07:53 PM	rwxr-xr-x
📄 aead.py	5.62 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 backend.py	94.95 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 ciphers.py	9.12 KB	02/29/2024 10:30:05 AM	rw-r--r--
📄 cmac.py	2.79 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 decode_asn1.py	32.52 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 dh.py	10.56 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 dsa.py	9.99 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 ec.py	12.29 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 ed25519.py	5.94 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 ed448.py	5.9 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 encode_asn1.py	23.04 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 hashes.py	3.12 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 hmac.py	2.93 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 ocsp.py	13.33 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 poly1305.py	2.3 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 rsa.py	17 KB	02/29/2024 10:30:05 AM	rw-r--r--
📄 utils.py	2.28 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 x25519.py	5.45 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 x448.py	4.42 KB	10/17/2019 01:00:23 PM	rw-r--r--
📄 x509.py	19.63 KB	10/17/2019 01:00:23 PM	rw-r--r--

Editing: aead.py

# This file is dual licensed under the terms of the Apache License, Version
# 2.0, and the BSD License. See the LICENSE file in the root of this repository
# for complete details.

from __future__ import absolute_import, division, print_function

from cryptography.exceptions import InvalidTag

_ENCRYPT = 1
_DECRYPT = 0

def _aead_cipher_name(cipher):
    from cryptography.hazmat.primitives.ciphers.aead import (
        AESCCM, AESGCM, ChaCha20Poly1305
    )
    if isinstance(cipher, ChaCha20Poly1305):
        return b"chacha20-poly1305"
    elif isinstance(cipher, AESCCM):
        return "aes-{}-ccm".format(len(cipher._key) * 8).encode("ascii")
    else:
        assert isinstance(cipher, AESGCM)
        return "aes-{}-gcm".format(len(cipher._key) * 8).encode("ascii")

def _aead_setup(backend, cipher_name, key, nonce, tag, tag_len, operation):
    evp_cipher = backend._lib.EVP_get_cipherbyname(cipher_name)
    backend.openssl_assert(evp_cipher != backend._ffi.NULL)
    ctx = backend._lib.EVP_CIPHER_CTX_new()
    ctx = backend._ffi.gc(ctx, backend._lib.EVP_CIPHER_CTX_free)
    res = backend._lib.EVP_CipherInit_ex(
        ctx, evp_cipher,
        backend._ffi.NULL,
        backend._ffi.NULL,
        backend._ffi.NULL,
        int(operation == _ENCRYPT)
    )
    backend.openssl_assert(res != 0)
    res = backend._lib.EVP_CIPHER_CTX_set_key_length(ctx, len(key))
    backend.openssl_assert(res != 0)
    res = backend._lib.EVP_CIPHER_CTX_ctrl(
        ctx, backend._lib.EVP_CTRL_AEAD_SET_IVLEN, len(nonce),
        backend._ffi.NULL
    )
    backend.openssl_assert(res != 0)
    if operation == _DECRYPT:
        res = backend._lib.EVP_CIPHER_CTX_ctrl(
            ctx, backend._lib.EVP_CTRL_AEAD_SET_TAG, len(tag), tag
        )
        backend.openssl_assert(res != 0)
    elif cipher_name.endswith(b"-ccm"):
        res = backend._lib.EVP_CIPHER_CTX_ctrl(
            ctx, backend._lib.EVP_CTRL_AEAD_SET_TAG, tag_len, backend._ffi.NULL
        )
        backend.openssl_assert(res != 0)

nonce_ptr = backend._ffi.from_buffer(nonce)
    key_ptr = backend._ffi.from_buffer(key)
    res = backend._lib.EVP_CipherInit_ex(
        ctx,
        backend._ffi.NULL,
        backend._ffi.NULL,
        key_ptr,
        nonce_ptr,
        int(operation == _ENCRYPT)
    )
    backend.openssl_assert(res != 0)
    return ctx

def _set_length(backend, ctx, data_len):
    intptr = backend._ffi.new("int *")
    res = backend._lib.EVP_CipherUpdate(
        ctx,
        backend._ffi.NULL,
        intptr,
        backend._ffi.NULL,
        data_len
    )
    backend.openssl_assert(res != 0)

def _process_aad(backend, ctx, associated_data):
    outlen = backend._ffi.new("int *")
    res = backend._lib.EVP_CipherUpdate(
        ctx, backend._ffi.NULL, outlen, associated_data, len(associated_data)
    )
    backend.openssl_assert(res != 0)

def _process_data(backend, ctx, data):
    outlen = backend._ffi.new("int *")
    buf = backend._ffi.new("unsigned char[]", len(data))
    res = backend._lib.EVP_CipherUpdate(ctx, buf, outlen, data, len(data))
    backend.openssl_assert(res != 0)
    return backend._ffi.buffer(buf, outlen[0])[:]

def _encrypt(backend, cipher, nonce, data, associated_data, tag_length):
    from cryptography.hazmat.primitives.ciphers.aead import AESCCM
    cipher_name = _aead_cipher_name(cipher)
    ctx = _aead_setup(
        backend, cipher_name, cipher._key, nonce, None, tag_length, _ENCRYPT
    )
    # CCM requires us to pass the length of the data before processing anything
    # However calling this with any other AEAD results in an error
    if isinstance(cipher, AESCCM):
        _set_length(backend, ctx, len(data))

_process_aad(backend, ctx, associated_data)
    processed_data = _process_data(backend, ctx, data)
    outlen = backend._ffi.new("int *")
    res = backend._lib.EVP_CipherFinal_ex(ctx, backend._ffi.NULL, outlen)
    backend.openssl_assert(res != 0)
    backend.openssl_assert(outlen[0] == 0)
    tag_buf = backend._ffi.new("unsigned char[]", tag_length)
    res = backend._lib.EVP_CIPHER_CTX_ctrl(
        ctx, backend._lib.EVP_CTRL_AEAD_GET_TAG, tag_length, tag_buf
    )
    backend.openssl_assert(res != 0)
    tag = backend._ffi.buffer(tag_buf)[:]

return processed_data + tag

def _decrypt(backend, cipher, nonce, data, associated_data, tag_length):
    from cryptography.hazmat.primitives.ciphers.aead import AESCCM
    if len(data) < tag_length:
        raise InvalidTag
    tag = data[-tag_length:]
    data = data[:-tag_length]
    cipher_name = _aead_cipher_name(cipher)
    ctx = _aead_setup(
        backend, cipher_name, cipher._key, nonce, tag, tag_length, _DECRYPT
    )
    # CCM requires us to pass the length of the data before processing anything
    # However calling this with any other AEAD results in an error
    if isinstance(cipher, AESCCM):
        _set_length(backend, ctx, len(data))

_process_aad(backend, ctx, associated_data)
    # CCM has a different error path if the tag doesn't match. Errors are
    # raised in Update and Final is irrelevant.
    if isinstance(cipher, AESCCM):
        outlen = backend._ffi.new("int *")
        buf = backend._ffi.new("unsigned char[]", len(data))
        res = backend._lib.EVP_CipherUpdate(ctx, buf, outlen, data, len(data))
        if res != 1:
            backend._consume_errors()
            raise InvalidTag

processed_data = backend._ffi.buffer(buf, outlen[0])[:]
    else:
        processed_data = _process_data(backend, ctx, data)
        outlen = backend._ffi.new("int *")
        res = backend._lib.EVP_CipherFinal_ex(ctx, backend._ffi.NULL, outlen)
        if res == 0:
            backend._consume_errors()
            raise InvalidTag

return processed_data