decompression of secp256r1 public keys

intel / tinycrypt

tinycrypt is a library of cryptographic algorithms with a focus on small, simple implementation.

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decompression of secp256r1 public keys #47

Open StefanHri opened 3 years ago

StefanHri commented 3 years ago

Hi,

I want to use uECC_shared_secret() to derive a shared secret. I have only the x coordinate of the public key. I assume the function uECC_shared_secret() requires the uncompressed key holding both coordinates {x,y}. How to decompress the public key? I found the following function in uECC link, however, this function appears to not be part of tinycrypt.