Exact format of ECDSA_SHA_256 public keys

Question

When I do a GetPublicKey of an asymmetric CMK key, I get back 91 bytes.  It looks like the last 65 bytes is the actual public key I need (starting at "04").  Can someone describe the format of this key in any detail?  Thank you.  
  
Maurice

Accepted Answer

Hi Maurice:  
  
KMS returns the public key as a Subject Public Key Info (SPKI) structure, as defined by RFC 5280 and its various references. We specifically return the key in the binary Distinguished Encoding Rules (DER) ASN.1 format.  
  
This format should be supported by most, if not all, common cryptographic libraries.   
  
Thanks for your feedback on how this wasn't as clear as it should have been - I'm going to work to get the KMS documentation updated to clarify.  
  
Please let me know if I can be of further assistance.  
  
Benjamin  
AWS KMS Team

Answer

Thank you.  Works for me.

Exact format of ECDSA_SHA_256 public keys

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