(pt, key, symbols="ABCDEFGHIJKLMNOPQRSTUVWXYZ")
return "".join(C)
Performs shift cipher encryption on plaintext pt, and returns the ciphertext.

    Notes
    =====

    The shift cipher is also called the Caesar cipher, after
    Julius Caesar, who, according to Suetonius, used it with a
    shift of three to protect messages of military significance.
    Caesar's nephew Augustus reportedtly used a similar cipher, but
    with a right shift of 1.


    ALGORITHM:

        INPUT:

            ``k``: an integer from 0 to 25 (the secret key)

            ``m``: string of upper-case letters (the plaintext message)

        OUTPUT:

            ``c``: string of upper-case letters (the ciphertext message)

        STEPS:
            0. Identify the alphabet A, ..., Z with the integers 0, ..., 25.
            1. Compute from the string ``m`` a list ``L1`` of corresponding
               integers.
            2. Compute from the list ``L1`` a new list ``L2``, given by
               adding ``(k mod 26)`` to each element in ``L1``.
            3. Compute from the list ``L2`` a string ``c`` of corresponding
               letters.

    Examples
    ========

    >>> from sympy.crypto.crypto import encipher_shift
    >>> pt = "GONAVYBEATARMY"
    >>> encipher_shift(pt, 1)
    'HPOBWZCFBUBSNZ'
    >>> encipher_shift(pt, 0)
    'GONAVYBEATARMY'
    >>> encipher_shift(pt, -1)
    'FNMZUXADZSZQLX'
Performs shift cipher encryption on plaintext pt, and returns the ciphertext.
Performs shift cipher encryption on plaintext pt and returns the ciphertext .
def encipher_shift(pt, key, symbols="ABCDEFGHIJKLMNOPQRSTUVWXYZ"):
    """
    Performs shift cipher encryption on plaintext pt, and returns the ciphertext.

    Notes
    =====

    The shift cipher is also called the Caesar cipher, after
    Julius Caesar, who, according to Suetonius, used it with a
    shift of three to protect messages of military significance.
    Caesar's nephew Augustus reportedtly used a similar cipher, but
    with a right shift of 1.


    ALGORITHM:

        INPUT:

            ``k``: an integer from 0 to 25 (the secret key)

            ``m``: string of upper-case letters (the plaintext message)

        OUTPUT:

            ``c``: string of upper-case letters (the ciphertext message)

        STEPS:
            0. Identify the alphabet A, ..., Z with the integers 0, ..., 25.
            1. Compute from the string ``m`` a list ``L1`` of corresponding
               integers.
            2. Compute from the list ``L1`` a new list ``L2``, given by
               adding ``(k mod 26)`` to each element in ``L1``.
            3. Compute from the list ``L2`` a string ``c`` of corresponding
               letters.

    Examples
    ========

    >>> from sympy.crypto.crypto import encipher_shift
    >>> pt = "GONAVYBEATARMY"
    >>> encipher_shift(pt, 1)
    'HPOBWZCFBUBSNZ'
    >>> encipher_shift(pt, 0)
    'GONAVYBEATARMY'
    >>> encipher_shift(pt, -1)
    'FNMZUXADZSZQLX'

    """
    symbols = "".join(symbols)
    A = alphabet_of_cipher(symbols)
    n = len(A)
    L = cycle_list(key, n)
    C = [A[(A.index(pt[i]) + key) % n] for i in range(len(pt))]
    return "".join(C)
def encipher_shift ( pt , key , symbols = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" ) : symbols = "" . join ( symbols ) A = alphabet_of_cipher ( symbols ) n = len ( A ) L = cycle_list ( key , n ) C = [ A [ ( A . index ( pt [ i ] ) + key ) % n ] for i in range ( len ( pt ) ) ] return "" . join ( C )