Aameek Singh

2005-10-31 18:24:19 UTC

Hello,

I am looking at a problem where encrypted data needs to be shared with users

and the aim is not to disclose the original key, rather modify the encrypted

data in a way that a new key can decrypt the data and only that key is

shared with the user.

In other words, given a key K, can we design Op and K2 such that:

D_K2 (Op (E_K (M))) = M

where D stands for decryption and E stands for encryption. Also, the security

of the encryption should not be affected (by much). I am open to the choice

of encryption scheme and the mode of operation (CBC, ECB, OFB...)

Any help will be appreciated.

Thanks,

Aameek

I am looking at a problem where encrypted data needs to be shared with users

and the aim is not to disclose the original key, rather modify the encrypted

data in a way that a new key can decrypt the data and only that key is

shared with the user.

In other words, given a key K, can we design Op and K2 such that:

D_K2 (Op (E_K (M))) = M

where D stands for decryption and E stands for encryption. Also, the security

of the encryption should not be affected (by much). I am open to the choice

of encryption scheme and the mode of operation (CBC, ECB, OFB...)

Any help will be appreciated.

Thanks,

Aameek