Hit send by accident before I finishing editing!
To make it more clear if a byte array is not padded then the unpaddedSize is self size.
What do you think?
Ron Teitelbaum
_____
From: Ron Teitelbaum [mailto:Ron@USMedRec.com] Sent: Thursday, July 06, 2006 11:08 PM To: 'Cryptography Team Development List' Subject: isProperlyPadded
Chris,
I ran into your padding methods which put the remainder size in each empty space after the real data.
I have a problem with
ByteArray>>unpaddedSize
"If I was padded by a BlockCipher, answer the size of the original plaintext."
self isProperlyPadded ifFalse: [ CryptographyError signal: 'Authentication failure (improperly padded!)' ].
^ self size - self last
Since isProperlyPadded assumes that that was some padding the error seems unnecessary.
Shouldn't this say:
ByteArray>>unpaddedSize
"If I was padded by a BlockCipher, answer the size of the original plaintext."
self isProperlyPadded ifFalse: [^self size].
^ self size - self last
Chris,
Ok so I'm thinking about this some more and wondering if the last byte is 1 wouldnt this method automatically chop the last byte off? Or if the last 2 bytes are 2 it would chop those off too. Isn't there a better way to determine if the byte array was padded? Maybe a subclass with an isPadded would make more sense?
What do you think?
Ron
From: Ron Teitelbaum Sent: Thursday, July 06, 2006 11:11 PM
Hit send by accident before I finishing editing!
To make it more clear if a byte array is not padded then the unpaddedSize is self size.
What do you think?
Ron Teitelbaum
________________________________________ From: Ron Teitelbaum [mailto:Ron@USMedRec.com] Sent: Thursday, July 06, 2006 11:08 PM To: 'Cryptography Team Development List' Subject: isProperlyPadded
Chris,
I ran into your padding methods which put the remainder size in each empty space after the real data.
I have a problem with
ByteArray>>unpaddedSize "If I was padded by a BlockCipher, answer the size of the original plaintext." self isProperlyPadded ifFalse: [ CryptographyError signal: 'Authentication failure (improperly padded!)' ]. ^ self size - self last
Since isProperlyPadded assumes that that was some padding the error seems unnecessary.
Shouldnt this say:
ByteArray>>unpaddedSize "If I was padded by a BlockCipher, answer the size of the original plaintext." self isProperlyPadded ifFalse: [^self size]. ^ self size - self last
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