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Beginner
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Clarification for sgx_ecc256_* set of APIs

Hi,

I found the SGX SDK has a set of ECC crypto APIs but the User Guide is not clear (IMHO) regarding how to use them. So I'm asking for clarification.

  • All of the APIs seem to require a sgx_ecc_state_handle_t. But nowhere is stated how this handle should be created. Any idea?
  • Can I get to specify the EC curve? If not, what is the default curve?

Thanks!

Fan

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Hi,

  • All of the APIs seem to require a sgx_ecc_state_handle_t. But nowhere is stated how this handle should be created. Any idea? - 
    sgx_ecc256_open_context:
    sgx_ecc256_open_context returns an allocated and initialized context for the elliptic curve cryptosystem over a prime finite field, GF(p). This context must be created prior to calling sgx_ecc256_create_key_pair or sgx_ecc256_compute_shared_dhkey. When the calling code has completed its set of ECC operations, sgx_ecc256_close_context should be called to cleanup and deallocate the ECC context.
  • Syntax: sgx_status_t sgx_ecc256_open_context( sgx_ecc_state_handle_t *p_ecc_handle );
  • Parameters: p_ecc_handle [out]
    This is a handle to the ECC GF(p) context state allocated and initialized used to perform elliptic curve cryptosystem standard functions. The algorithm stores the intermediate results of calculations performed using this context.

-Surenthar

- Surenthar Selvaraj
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Beginner
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Interesting. The documentation (https://software.intel.com/sites/products/sgx-sdk-users-guide-windows/Default.htm) I'm reading says the opposite ([in] v.s. [out]):

Screen Shot 2016-11-21 at 12.20.49 PM.png

I guess you're right and the documentation has a typo?

Surenthar Selvaraj. (Intel) wrote:

Hi,

  • All of the APIs seem to require a sgx_ecc_state_handle_t. But nowhere is stated how this handle should be created. Any idea? - 
    sgx_ecc256_open_context:
    sgx_ecc256_open_context returns an allocated and initialized context for the elliptic curve cryptosystem over a prime finite field, GF(p). This context must be created prior to calling sgx_ecc256_create_key_pair or sgx_ecc256_compute_shared_dhkey. When the calling code has completed its set of ECC operations, sgx_ecc256_close_context should be called to cleanup and deallocate the ECC context.
  • Syntax: sgx_status_t sgx_ecc256_open_context( sgx_ecc_state_handle_t *p_ecc_handle );
  • Parameters: p_ecc_handle [out]
    This is a handle to the ECC GF(p) context state allocated and initialized used to perform elliptic curve cryptosystem standard functions. The algorithm stores the intermediate results of calculations performed using this context.

-Surenthar

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Employee
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Note that the HTML version of the User's Guide is out-of-date.

Please refer to the PDF document instead.

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