This question concerns block cipher padding. Suppose the block cipher has a block size of 18 bytes. A certain message ends with a partial block which is 5 bytes. We must reversibly pad out the message to use some block cipher modes, such as CBC (even if the last block is full). Consider the following padding strategy. Append a single byte with value 128, and then as many zero bytes as required make the overall length a multiple of 18. Suppose the final (possibly partial) block of the message is "0x0001020304" in hexadecimal. Write out the complete final block in hexadecimal. Please do not put a leading Ox as this has been written already. Ox

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This question concerns block cipher padding. Suppose the block cipher has a block size of 18 bytes. A certain message ends with a partial block which is 5 bytes. We must reversibly pad out the
to use some block cipher modes, such as CBC (even if the last block is full).
message
Consider the following padding strategy.
Append a single byte with value 128, and then as many zero bytes as required to make the overall length a multiple of 18.
Suppose the final (possibly partial) block of the message is "0x0001020304" in hexadecimal. Write out the complete final block in hexadecimal. Please do not put a leading Ox as this has been written already.
Ox
Transcribed Image Text:This question concerns block cipher padding. Suppose the block cipher has a block size of 18 bytes. A certain message ends with a partial block which is 5 bytes. We must reversibly pad out the to use some block cipher modes, such as CBC (even if the last block is full). message Consider the following padding strategy. Append a single byte with value 128, and then as many zero bytes as required to make the overall length a multiple of 18. Suppose the final (possibly partial) block of the message is "0x0001020304" in hexadecimal. Write out the complete final block in hexadecimal. Please do not put a leading Ox as this has been written already. Ox
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