Python crypto_box_open_afternmの例

コード例 #1

def crypto_box_open_afternm(ciphertext, nonce, k):
    """
    Decrypts and returns the encrypted message ``ciphertext``, using the shared
    key ``k`` and the nonce ``nonce``.

    :param ciphertext: bytes
    :param nonce: bytes
    :param k: bytes
    :rtype: bytes
    """
    if len(nonce) != crypto_box_NONCEBYTES:
        raise exc.ValueError("Invalid nonce")

    if len(k) != crypto_box_BEFORENMBYTES:
        raise exc.ValueError("Invalid shared key")

    padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
    plaintext = ffi.new("unsigned char[]", len(padded))

    res = lib.crypto_box_open_afternm(plaintext, padded, len(padded), nonce, k)
    ensure(res == 0,
           "An error occurred trying to decrypt the message",
           raising=exc.CryptoError)

    return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]

コード例 #2

ファイル: crypto_box.py プロジェクト: maqp/pynacl

def crypto_box_open_afternm(ciphertext, nonce, k):
    """
    Decrypts and returns the encrypted message ``ciphertext``, using the shared
    key ``k`` and the nonce ``nonce``.

    :param ciphertext: bytes
    :param nonce: bytes
    :param k: bytes
    :rtype: bytes
    """
    if len(nonce) != crypto_box_NONCEBYTES:
        raise exc.ValueError("Invalid nonce")

    if len(k) != crypto_box_BEFORENMBYTES:
        raise exc.ValueError("Invalid shared key")

    padded = (b"\x00" * crypto_box_BOXZEROBYTES) + ciphertext
    plaintext = ffi.new("unsigned char[]", len(padded))

    res = lib.crypto_box_open_afternm(
                plaintext, padded, len(padded), nonce, k)
    ensure(res == 0, "An error occurred trying to decrypt the message",
           raising=exc.CryptoError)

    return ffi.buffer(plaintext, len(padded))[crypto_box_ZEROBYTES:]