Suppose we have the encoding that enables Carol to mount the cube root attack (see The Cube Root Problem). If Carol sends a message to Bob, supposedly signed by you, will there be anything suspicious and noticeable about the signed message, so that with very little additional computation Bob can detect the forgery? Is there anything Carol can do to make her messages less suspicious? Cuberoot problem: Let's say you pad on the right with random data. You chose that scheme so that there is a negligible probability that anything you sign will be smooth. However, if the public exponent is 3, this enables Carol to forge your signature on virtually any message she chooses! Let's say Carol wants your signature on some message. The message digest of that message is h. Carol pads h on the right with zeroes. She then computes its ordinary cube root and rounds up to an integer r. Now she has forged your signature, because re = r3 = (h padded on the right with a seemingly random number).
Suppose we have the encoding that enables Carol to mount the cube root attack (see The Cube Root Problem). If Carol sends a message to Bob, supposedly signed by you, will there be anything suspicious and noticeable about the signed message, so that with very little additional computation Bob can detect the forgery? Is there anything Carol can do to make her messages less suspicious?
Cuberoot problem:
Let's say you pad on the right with random data. You chose that scheme so that there is a negligible probability that anything you sign will be smooth. However, if the public exponent is 3, this enables Carol to forge your signature on virtually any message she chooses!
Let's say Carol wants your signature on some message. The message digest of that message is h. Carol pads h on the right with zeroes. She then computes its ordinary cube root and rounds up to an integer r. Now she has forged your signature, because re = r3 = (h padded on the right with a seemingly random number).
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 2 images
