3 ms·

Encrypt pictures using a public key stored on the SD card have the secret key known only to your lawyer who lives in another country.

• bdamm 10y ago
  Too slow. RSA encryption is very expensive. Also, RSA keys are enormous. Much better is to derive a symmetric key from your private key exchange with your lawyer, and use that to encrypt the pictures. The camera or card could have a "wipe" switch that erases its local copy of the symmetric key, leaving only the lawyer being able to decrypt the photos that have been taken.
  • garrettr_ 10y ago
    > Too slow. RSA encryption is very expensive. So use a public-key algorithm that is designed to be faster, less expensive, and use smaller keys -- e.g. NaCl's crypto_box, which uses Curve25519 under the hood: https://nacl.cr.yp.to/box.html https://nacl.cr.yp.to/box.html. > Also, RSA keys are enormous. We're talking about devices that have as a primary goal the storage of lots of high-resolution media (photographs and video). I think you could find a couple extra KB to spare for an RSA public key... (although, again, there are better primitives than RSA that should be preferred).
  • EthanHeilman 10y ago
    Give lawyer x, encrypt the first picture under H(x), the second under H(H(x)), and so on. Always delete the key after you use it so that the data can not be recovered without x.
  • EthanHeilman 10y ago
    Give lawyer x, encrypt the first picture under H(x), the second under H(H(x)), and so on. Always delete the key after you use it so that the data can not be recovered without x.