This adds ed25519 signature support using the "prehash" method. Instead
of using the direct contents of the image and header payloads, a sha256
is generated and signed (SHA256-Ed25519). This allows for compatibility
with already existing tools that use the sha256 hash, like mcumgr, etc.
Signed-off-by: Fabio Utzig <utzig@apache.org>
imgtool verify -k <some-key.(pub|sec)> <img-file>
Allow imgtool to validate that an image has a valid sha256sum and that
it was signed by the supplied key.
NOTE: this does not yet support verifying encrypted images
Signed-off-by: Fabio Utzig <utzig@apache.org>
Until we fix the padding problem, pad the ecdsa signatures with zeros to
always be 72 bytes long. Add a 'raw_sign' method so that the unit test
can use the real signature.
Signed-off-by: David Brown <david.brown@linaro.org>
Replace the (now broken) ECDSA code with code using the python
'cryptography' library.
Similar to the change to RSA, this changes the format that private keys
are stored, again using PKCS#8. This supports the stronger password
protection as well.
Again, this code will still support reading the older style of public
keys, but other tools that use keys generated by this change will need
to be updated to work with the new format.
Signed-off-by: David Brown <david.brown@linaro.org>
The verification code requires a fixed 32-byte salt, which seems is what
the old crypto library did. Use this same value to avoid having to
modify the code.
Signed-off-by: David Brown <david.brown@linaro.org>
The keygen command allows the `-p` argument which will prompt for a
password, and protect the private key with this password. When loading
keys, it will prompt for a password if it detects a password protected
key.
Signed-off-by: David Brown <david.brown@linaro.org>
Replace RSA code with one using the python 'cryptography' library. This
library is much more complete, and will make adding support for password
protected keys, and separate public keys easier.
There is, however, a significant change brought about by this change:
the private keys are stored in PKCS#8 format, instead of the raw format
that was used previously. This is a more modern format that has a few
advantages, including: supporting stronger password protection, and
allowing the key type to be determined upon read.
This tool will still support reading the old style public keys, but
other tools that use these keys will need to be updated in order to work
with the new format.
This new code has some unit tests to go along with it for some basic
sanity testing of the code.
Signed-off-by: David Brown <david.brown@linaro.org>
Fabio Utzig