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def encode_base64(text):

r"""

>>> encode_base64('WELCOME to base64 encoding 😁')

'V0VMQ09NRSB0byBiYXNlNjQgZW5jb2Rpbmcg8J+YgQ=='

>>> encode_base64('AÅᐃ𐀏🤓')

'QcOF4ZCD8JCAj/CfpJM='

>>> encode_base64('A'*60)

'QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFB\r\nQUFB'

"""

base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

byte_text = bytes(text, "utf-8") # put text in bytes for unicode support

r = "" # the result

c = -len(byte_text) % 3 # the length of padding

p = "=" * c # the padding

s = byte_text + b"\x00" * c # the text to encode

i = 0

while i < len(s):

if i > 0 and ((i / 3 * 4) % 76) == 0:

r = r + "\r\n" # for unix newline, put "\n"

n = (s[i] << 16) + (s[i + 1] << 8) + s[i + 2]

n1 = (n >> 18) & 63

n2 = (n >> 12) & 63

n3 = (n >> 6) & 63

n4 = n & 63

r += base64_chars[n1] + base64_chars[n2] + base64_chars[n3] + base64_chars[n4]

i += 3

return r[0 : len(r) - len(p)] + p

def decode_base64(text):

r"""

>>> decode_base64('V0VMQ09NRSB0byBiYXNlNjQgZW5jb2Rpbmcg8J+YgQ==')

'WELCOME to base64 encoding 😁'

>>> decode_base64('QcOF4ZCD8JCAj/CfpJM=')

'AÅᐃ𐀏🤓'

>>> decode_base64("QUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUF"

... "BQUFBQUFBQUFB\r\nQUFB")

'AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA'

"""

base64_chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

s = ""

for i in text:

if i in base64_chars:

s += i

c = ""

else:

if i == "=":

c += "="

p = ""

if c == "=":

p = "A"

else:

if c == "==":

p = "AA"

r = b""

s = s + p

i = 0

while i < len(s):

n = (

(base64_chars.index(s[i]) << 18)

+ (base64_chars.index(s[i + 1]) << 12)

+ (base64_chars.index(s[i + 2]) << 6)

+ base64_chars.index(s[i + 3])

)

r += bytes([(n >> 16) & 255]) + bytes([(n >> 8) & 255]) + bytes([n & 255])

i += 4

return str(r[0 : len(r) - len(p)], "utf-8")

def main():

print(encode_base64("WELCOME to base64 encoding 😁"))

print(decode_base64(encode_base64("WELCOME to base64 encoding 😁")))

if __name__ == "__main__":

main()

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base64_cipher.py

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base64_cipher.py

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