Mixing
Error decoding incorrect paddling with decode64, with padding present?
With the code that I am using, every time there is a "?" on data of the encoded message I get an error back "Incorrect Padding". When using a decoder online I get the correct value for both value1 and value2 below, but for value2 where there should be a "?" I get an exception instead.
The code is:
value1 = "Y29udGludWENCg=="
expected1 = b'continuarn'
value2 = "Y29udGludWE_DQo="
expected2 = b'continua?rn'
data1 = base64.b64decode(value1)
assert data1 == expected1
data2 = base64.b64decode(value2)
assert data2 == expected2
Decoding value2 throws a binascii.Error: Incorrect padding exception, but the data has the right amount of padding (the length of value2 is a multiple of 4).
python base64 decode
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
add a comment |
With the code that I am using, every time there is a "?" on data of the encoded message I get an error back "Incorrect Padding". When using a decoder online I get the correct value for both value1 and value2 below, but for value2 where there should be a "?" I get an exception instead.
The code is:
value1 = "Y29udGludWENCg=="
expected1 = b'continuarn'
value2 = "Y29udGludWE_DQo="
expected2 = b'continua?rn'
data1 = base64.b64decode(value1)
assert data1 == expected1
data2 = base64.b64decode(value2)
assert data2 == expected2
Decoding value2 throws a binascii.Error: Incorrect padding exception, but the data has the right amount of padding (the length of value2 is a multiple of 4).
python base64 decode
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Just add the missing'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add=characters until it is.
– Martijn Pieters♦
Nov 20 '18 at 8:23
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
Ah, I see what is going on: You have URL-safe data. Usebase64.urlsafe_b64decode().
– Martijn Pieters♦
Nov 20 '18 at 8:35
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33
add a comment |
With the code that I am using, every time there is a "?" on data of the encoded message I get an error back "Incorrect Padding". When using a decoder online I get the correct value for both value1 and value2 below, but for value2 where there should be a "?" I get an exception instead.
The code is:
value1 = "Y29udGludWENCg=="
expected1 = b'continuarn'
value2 = "Y29udGludWE_DQo="
expected2 = b'continua?rn'
data1 = base64.b64decode(value1)
assert data1 == expected1
data2 = base64.b64decode(value2)
assert data2 == expected2
Decoding value2 throws a binascii.Error: Incorrect padding exception, but the data has the right amount of padding (the length of value2 is a multiple of 4).
python base64 decode
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
With the code that I am using, every time there is a "?" on data of the encoded message I get an error back "Incorrect Padding". When using a decoder online I get the correct value for both value1 and value2 below, but for value2 where there should be a "?" I get an exception instead.
The code is:
value1 = "Y29udGludWENCg=="
expected1 = b'continuarn'
value2 = "Y29udGludWE_DQo="
expected2 = b'continua?rn'
data1 = base64.b64decode(value1)
assert data1 == expected1
data2 = base64.b64decode(value2)
assert data2 == expected2
Decoding value2 throws a binascii.Error: Incorrect padding exception, but the data has the right amount of padding (the length of value2 is a multiple of 4).
python base64 decode
python base64 decode
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
edited Nov 20 '18 at 10:32
Martijn Pieters♦
704k13324522279
704k13324522279
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
asked Nov 20 '18 at 8:18
joao santanajoao santana
95
95
Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Just add the missing'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add=characters until it is.
– Martijn Pieters♦
Nov 20 '18 at 8:23
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
Ah, I see what is going on: You have URL-safe data. Usebase64.urlsafe_b64decode().
– Martijn Pieters♦
Nov 20 '18 at 8:35
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33
add a comment |
Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Just add the missing'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add=characters until it is.
– Martijn Pieters♦
Nov 20 '18 at 8:23
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
Ah, I see what is going on: You have URL-safe data. Usebase64.urlsafe_b64decode().
– Martijn Pieters♦
Nov 20 '18 at 8:35
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33
Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Just add the missing
'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add = characters until it is.– Martijn Pieters♦
Nov 20 '18 at 8:23
Just add the missing
'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add = characters until it is.– Martijn Pieters♦
Nov 20 '18 at 8:23
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
Ah, I see what is going on: You have URL-safe data. Use
base64.urlsafe_b64decode().– Martijn Pieters♦
Nov 20 '18 at 8:35
Ah, I see what is going on: You have URL-safe data. Use
base64.urlsafe_b64decode().– Martijn Pieters♦
Nov 20 '18 at 8:35
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33
add a comment |
1 Answer
1
active
oldest
votes
You do not have standard Base64 data, you have URL-safe base64 data.
Base64 normally uses letters, digits and / and + characters, but the latter two carry special meaning in URLs, so an alternative Base64url encoding is used that uses - and _ characters instead.
Use the base64.urlsafe_b64decode() function to decode these strings:
data2 = base64.urlsafe_b64decode(value2)
Demo:
>>> import base64
>>> value2 = "Y29udGludWE_DQo="
>>> base64.urlsafe_b64decode(value2)
b'continua?rn'
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
You do not have standard Base64 data, you have URL-safe base64 data.
Base64 normally uses letters, digits and / and + characters, but the latter two carry special meaning in URLs, so an alternative Base64url encoding is used that uses - and _ characters instead.
Use the base64.urlsafe_b64decode() function to decode these strings:
data2 = base64.urlsafe_b64decode(value2)
Demo:
>>> import base64
>>> value2 = "Y29udGludWE_DQo="
>>> base64.urlsafe_b64decode(value2)
b'continua?rn'
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
add a comment |
You do not have standard Base64 data, you have URL-safe base64 data.
Base64 normally uses letters, digits and / and + characters, but the latter two carry special meaning in URLs, so an alternative Base64url encoding is used that uses - and _ characters instead.
Use the base64.urlsafe_b64decode() function to decode these strings:
data2 = base64.urlsafe_b64decode(value2)
Demo:
>>> import base64
>>> value2 = "Y29udGludWE_DQo="
>>> base64.urlsafe_b64decode(value2)
b'continua?rn'
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
add a comment |
You do not have standard Base64 data, you have URL-safe base64 data.
Base64 normally uses letters, digits and / and + characters, but the latter two carry special meaning in URLs, so an alternative Base64url encoding is used that uses - and _ characters instead.
Use the base64.urlsafe_b64decode() function to decode these strings:
data2 = base64.urlsafe_b64decode(value2)
Demo:
>>> import base64
>>> value2 = "Y29udGludWE_DQo="
>>> base64.urlsafe_b64decode(value2)
b'continua?rn'
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
You do not have standard Base64 data, you have URL-safe base64 data.
Base64 normally uses letters, digits and / and + characters, but the latter two carry special meaning in URLs, so an alternative Base64url encoding is used that uses - and _ characters instead.
Use the base64.urlsafe_b64decode() function to decode these strings:
data2 = base64.urlsafe_b64decode(value2)
Demo:
>>> import base64
>>> value2 = "Y29udGludWE_DQo="
>>> base64.urlsafe_b64decode(value2)
b'continua?rn'
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
edited Nov 20 '18 at 10:37
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
answered Nov 20 '18 at 8:37
Martijn Pieters♦Martijn Pieters
704k13324522279
704k13324522279
add a comment |
add a comment |
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Your base64 padding is indeed invalid. It can be repaired, which is what an online decoder might have done.
– Martijn Pieters♦
Nov 20 '18 at 8:21
Just add the missing
'='. Remove all non-Base64 characters first, then if the length is not a multiple of 4, add=characters until it is.– Martijn Pieters♦
Nov 20 '18 at 8:23
could you show me a exemple martijn?
– joao santana
Nov 20 '18 at 8:26
Ah, I see what is going on: You have URL-safe data. Use
base64.urlsafe_b64decode().– Martijn Pieters♦
Nov 20 '18 at 8:35
In future, start with a complete Minimal, Complete, and Verifiable example; I've filled in the blanks here once I figured out what kind of data you were expecting. Don't leave people trying to help you to guess.
– Martijn Pieters♦
Nov 20 '18 at 10:33