RSA padding questions

assume a plaintext of 'm1', encrypted using RSA and standard OAEP
padding, to produce a ciphertext 'c'


is it possible to construct a different padding system, so that a
different plaintext 'm2',
encrypted with the same RSA key, but with the new padding,
still produces the same ciphertext 'c' ?

the goal here is to secure the messages after 'leaking' the RSA key


now, since the person who wants to send the message of 'real' content,
'm2',
is also the one composing 'm1',
there may be some latitude in the composition of 'm1' to make it easier
to construct
the padding for 'm2'

alternatively,
shouldn't it at least be possible to construct 'm2' first, then the
padding, and obtain 'c',
and then have 'm1' be any gibberish random text that would encrypt to
'c' using standard
OAEP padding

the gibberish text may plausibly be considered an 'already encrypted'
message,
that is then RSA encrypted

is this practically possible,
or only theoretically so, but with the same infeasability of
constructing a collision ?


TIA,

vedaal

.

Relevant Pages

  • Re: ADVERT: Secure communications
    ... it "hides" ciphertext in padding? ... | eliminating security risks from symmetric ciphers. ... The security of RSA isn't even proven, ... encrypt with RSA. ...
    (comp.os.linux.security)
  • Re: asymmetric encryption options
    ... now I am generating a random key, encrypting the data with it using ... then encrypting the key with rsa. ... You can split the longer key into blocks, and encrypt them alone. ... The original padding is really simple to implement, ...
    (comp.lang.ruby)
  • RSA // linking plaintext to ciphertext
    ... >> the plaintext), ... >> ciphertext, ... which is not not the same as the known ciphertext when padding is ... even if encrypt, then sign or sign&encrypt, is used, ...
    (sci.crypt)
  • Re: RSA Encryption
    ... this is a limit set by the RSA 1024 bit algorithm. ... William Stacey [MVP] wrote: ... Maybe you can if no padding is used, ... so a larger key can encrypt more bytes. ...
    (microsoft.public.dotnet.languages.csharp)
  • Re: AES encryption with Java
    ... There is at least one padding byte. ... I'm pretty sure that if you encrypt plaintext that is 16 ... bytes long you should receive ciphertext that is 16 bytes long. ... I'm encrypting 16 byte plaintext and ending up with 32 byte ...
    (comp.lang.java.security)