def pbkdf1(hash_algorithm, password, salt, iterations, key_length):
    """
    An implementation of PBKDF1 - should only be used for interop with legacy
    systems, not new architectures

    :param hash_algorithm:
        The string name of the hash algorithm to use: "md2", "md5", "sha1"

    :param password:
        A byte string of the password to use an input to the KDF

    :param salt:
        A cryptographic random byte string

    :param iterations:
        The numbers of iterations to use when deriving the key

    :param key_length:
        The length of the desired key in bytes

    :return:
        The derived key as a byte string
    """

    if not isinstance(password, byte_cls):
        raise TypeError(pretty_message(
            '''
            password must be a byte string, not %s
            ''',
            (type_name(password))
        ))

    if not isinstance(salt, byte_cls):
        raise TypeError(pretty_message(
            '''
            salt must be a byte string, not %s
            ''',
            (type_name(salt))
        ))

    if not isinstance(iterations, int_types):
        raise TypeError(pretty_message(
            '''
            iterations must be an integer, not %s
            ''',
            (type_name(iterations))
        ))

    if iterations < 1:
        raise ValueError(pretty_message(
            '''
            iterations must be greater than 0 - is %s
            ''',
            repr(iterations)
        ))

    if not isinstance(key_length, int_types):
        raise TypeError(pretty_message(
            '''
            key_length must be an integer, not %s
            ''',
            (type_name(key_length))
        ))

    if key_length < 1:
        raise ValueError(pretty_message(
            '''
            key_length must be greater than 0 - is %s
            ''',
            repr(key_length)
        ))

    if hash_algorithm not in set(['md2', 'md5', 'sha1']):
        raise ValueError(pretty_message(
            '''
            hash_algorithm must be one of "md2", "md5", "sha1", not %s
            ''',
            repr(hash_algorithm)
        ))

    if key_length > 16 and hash_algorithm in set(['md2', 'md5']):
        raise ValueError(pretty_message(
            '''
            key_length can not be longer than 16 for %s - is %s
            ''',
            (hash_algorithm, repr(key_length))
        ))

    if key_length > 20 and hash_algorithm == 'sha1':
        raise ValueError(pretty_message(
            '''
            key_length can not be longer than 20 for sha1 - is %s
            ''',
            repr(key_length)
        ))

    algo = getattr(hashlib, hash_algorithm)
    output = algo(password + salt).digest()
    for _ in range(2, iterations + 1):
        output = algo(output).digest()

    return output[:key_length]
def pbkdf1(hash_algorithm, password, salt, iterations, key_length):
    """
    An implementation of PBKDF1 - should only be used for interop with legacy
    systems, not new architectures

    :param hash_algorithm:
        The string name of the hash algorithm to use: "md2", "md5", "sha1"

    :param password:
        A byte string of the password to use an input to the KDF

    :param salt:
        A cryptographic random byte string

    :param iterations:
        The numbers of iterations to use when deriving the key

    :param key_length:
        The length of the desired key in bytes

    :return:
        The derived key as a byte string
    """

    if not isinstance(password, byte_cls):
        raise TypeError(pretty_message(
            '''
            password must be a byte string, not %s
            ''',
            (type_name(password))
        ))

    if not isinstance(salt, byte_cls):
        raise TypeError(pretty_message(
            '''
            salt must be a byte string, not %s
            ''',
            (type_name(salt))
        ))

    if not isinstance(iterations, int_types):
        raise TypeError(pretty_message(
            '''
            iterations must be an integer, not %s
            ''',
            (type_name(iterations))
        ))

    if iterations < 1:
        raise ValueError(pretty_message(
            '''
            iterations must be greater than 0 - is %s
            ''',
            repr(iterations)
        ))

    if not isinstance(key_length, int_types):
        raise TypeError(pretty_message(
            '''
            key_length must be an integer, not %s
            ''',
            (type_name(key_length))
        ))

    if key_length < 1:
        raise ValueError(pretty_message(
            '''
            key_length must be greater than 0 - is %s
            ''',
            repr(key_length)
        ))

    if hash_algorithm not in set(['md2', 'md5', 'sha1']):
        raise ValueError(pretty_message(
            '''
            hash_algorithm must be one of "md2", "md5", "sha1", not %s
            ''',
            repr(hash_algorithm)
        ))

    if key_length > 16 and hash_algorithm in set(['md2', 'md5']):
        raise ValueError(pretty_message(
            '''
            key_length can not be longer than 16 for %s - is %s
            ''',
            (hash_algorithm, repr(key_length))
        ))

    if key_length > 20 and hash_algorithm == 'sha1':
        raise ValueError(pretty_message(
            '''
            key_length can not be longer than 20 for sha1 - is %s
            ''',
            repr(key_length)
        ))

    algo = getattr(hashlib, hash_algorithm)
    output = algo(password + salt).digest()
    for _ in range(2, iterations + 1):
        output = algo(output).digest()

    return output[:key_length]
def pbkdf1 ( hash_algorithm , password , salt , iterations , key_length ) : if not isinstance ( password , byte_cls ) : raise TypeError ( pretty_message ( '''
            password must be a byte string, not %s
            ''' , ( type_name ( password ) ) ) ) if not isinstance ( salt , byte_cls ) : raise TypeError ( pretty_message ( '''
            salt must be a byte string, not %s
            ''' , ( type_name ( salt ) ) ) ) if not isinstance ( iterations , int_types ) : raise TypeError ( pretty_message ( '''
            iterations must be an integer, not %s
            ''' , ( type_name ( iterations ) ) ) ) if iterations < 1 : raise ValueError ( pretty_message ( '''
            iterations must be greater than 0 - is %s
            ''' , repr ( iterations ) ) ) if not isinstance ( key_length , int_types ) : raise TypeError ( pretty_message ( '''
            key_length must be an integer, not %s
            ''' , ( type_name ( key_length ) ) ) ) if key_length < 1 : raise ValueError ( pretty_message ( '''
            key_length must be greater than 0 - is %s
            ''' , repr ( key_length ) ) ) if hash_algorithm not in set ( [ 'md2' , 'md5' , 'sha1' ] ) : raise ValueError ( pretty_message ( '''
            hash_algorithm must be one of "md2", "md5", "sha1", not %s
            ''' , repr ( hash_algorithm ) ) ) if key_length > 16 and hash_algorithm in set ( [ 'md2' , 'md5' ] ) : raise ValueError ( pretty_message ( '''
            key_length can not be longer than 16 for %s - is %s
            ''' , ( hash_algorithm , repr ( key_length ) ) ) ) if key_length > 20 and hash_algorithm == 'sha1' : raise ValueError ( pretty_message ( '''
            key_length can not be longer than 20 for sha1 - is %s
            ''' , repr ( key_length ) ) ) algo = getattr ( hashlib , hash_algorithm ) output = algo ( password + salt ) . digest ( ) for _ in range ( 2 , iterations + 1 ) : output = algo ( output ) . digest ( ) return output [ : key_length ]
An implementation of PBKDF1 - should only be used for interop with legacy
    systems, not new architectures

    :param hash_algorithm:
        The string name of the hash algorithm to use: "md2", "md5", "sha1"

    :param password:
        A byte string of the password to use an input to the KDF

    :param salt:
        A cryptographic random byte string

    :param iterations:
        The numbers of iterations to use when deriving the key

    :param key_length:
        The length of the desired key in bytes

    :return:
        The derived key as a byte string
An implementation of PBKDF1 - should only be used for interop with legacy systems not new architectures