On 2/16/24 14:27, Simo Sorce wrote:
> On Thu, 2024-02-15 at 18:13 -0500, Stefan Berger wrote:
>> This series of patches adds support for the NIST P521 curve to ecdsa and
>> ecdh. Test cases for NIST P521 are added to both modules.
>>
>> An issue with the current code in ecdsa and ecdh is that it assumes that
>> input arrays providing key coordinates for example, are arrays of digits
>> (a 'digit' is a 'u64'). This works well for all currently supported
>> curves, such as NIST P192/256/384, but does not work for NIST P521 where
>> coordinates are 8 digits + 2 bytes long. So some of the changes deal with
>> converting byte arrays to digits and digits to byte arrays.
>>
>>
>> Regards,
>> Stefan
>>
>> v2:
>> - Reformulated some patch descriptions
>> - Fixed issue detected by krobot
>> - Some other small changes to the code
>>
>> Stefan Berger (14):
>> crypto: ecdsa - Convert byte arrays with key coordinates to digits
>> crypto: ecdsa - Adjust tests on length of key parameters
>> crypto: ecdsa - Extend res.x mod n calculation for NIST P521
>> crypto: ecc - Implement vli_mmod_fast_521 for NIST p521
>> crypto: ecc - For NIST P521 use vli_num_bits to get number of bits
>> crypto: ecc - Add NIST P521 curve parameters
>> crypto: ecdsa - Register NIST P521 and extend test suite
>> x509: Add OID for NIST P521 and extend parser for it
>> crypto: ecdh - Use properly formatted digits to check for valid key
>> crypto: ecc - Implement ecc_digits_to_bytes to convert digits to byte
>> array
>> crypto: Add nbits field to ecc_curve structure
>> crypto: ecc - Implement and use ecc_curve_get_nbytes to get curve's
>> nbytes
>> crypto: ecdh - Use functions to copy digits from and to byte array
>> crypto: ecdh - Add support for NIST P521 and add test case
>>
>> crypto/asymmetric_keys/x509_cert_parser.c | 3 +
>> crypto/ecc.c | 71 +++++--
>> crypto/ecc_curve_defs.h | 45 +++++
>> crypto/ecdh.c | 59 +++++-
>> crypto/ecdsa.c | 48 ++++-
>> crypto/testmgr.c | 14 ++
>> crypto/testmgr.h | 225 ++++++++++++++++++++++
>> include/crypto/ecc_curve.h | 3 +
>> include/crypto/ecdh.h | 1 +
>> include/crypto/internal/ecc.h | 61 +++++-
>> include/linux/oid_registry.h | 1 +
>> 11 files changed, 495 insertions(+), 36 deletions(-)
>
> Hi Stefan,
> what kind of side-channel testing was performed on this code?
> And what is the use case you are adding it for?
We're using public keys for signature verification. I am not aware that
public key usage is critical to side channels.
The use case for adding it is primarily driven by closing a gap to
complete the support for the common ECDSA NIST curves.
Stefan
>
> Thanks,
> Simo.
>