This commit adds a flag to the RSA import/export tests indicating whether it is
expected that a full RSA keypair can be set up from the provided parameters.
Further, the tests of `mbedtls_rsa_import` and `mbedtls_rsa_import_raw` are
expanded to perform key checks and an example encryption-decryption.
This commit changes the implementation of `mbedtls_rsa_get_len` to return
`ctx->len` instead of always re-computing the modulus' byte-size via
`mbedtls_mpi_size`.
This commit adds the function mbedtls_rsa_validate_crt for validating a set of CRT parameters. The function
mbedtls_rsa_check_crt is simplified accordingly.
Primality testing is guarded by the configuration flag MBEDTLS_GENPRIME and used in the new RSA helper functions. This
commit adds a corresponding preprocessor directive.
Alternative RSA implementations can be provided by defining MBEDTLS_RSA_ALT in
config.h, defining an mbedtls_rsa_context struct in a new file rsa_alt.h and
re-implementing the RSA interface specified in rsa.h.
Through the previous reworkings, the adherence to the interface is the only
implementation obligation - in particular, implementors are free to use a
different layout for the RSA context structure.
This commit adds test for the new library function mbedtls_rsa_check_params for
checking a set of RSA core parameters. There are some toy example tests with
small numbers that can be verified by hand, as well as tests with real world
numbers. Complete, partial and corrupted data are tested, as well the check for
primality exactly if a PRNG is provided.
This commit adds tests for the new library function mbedtls_rsa_export_raw.
Each test case performs the following steps:
- Parse and convert a set of hex-string decoded core RSA parameters into big
endian byte arrays.
- Use these to initialize an RSA context
- Export core RSA parameters as byte arrays again afterwards
- Compare byte strings.
Each test split is performed twice, once with successive and once with
simultaneous exporting.
