Jan Luehr wrote: > 1st. Encrypting information twice. > For instance: An RSA encrypted mail is stored on a loop-aes encrypted > harddrive. (If you think of XOR, you run into serious problems, if using same > keys, but I guess RSA and AES won't be a problem at all.) Some block cipher operating modes, such as OFB and CTR, use block cipher as sort of PRNG and XOR the plaintext with PRNG output. Applying two such layers of encryption, using identical key and IV at same data offset, will effectively cancel each other out. Loop-AES uses CBC mode so above does not apply to it. > 2nd. Encrypting information more times. > For instance: Backups are done on removeable media. Each one is encrypted with > a different set of keys for loop-aes, but also containing very similar data. No problem there. -- Jari Ruusu 1024R/3A220F51 5B 4B F9 BB D3 3F 52 E9 DB 1D EB E3 24 0E A9 DD - Linux-crypto: cryptography in and on the Linux system Archive: http://mail.nl.linux.org/linux-crypto/
