topic X25519 algoritm doesn't generate the correct key in Secure Authentication https://community.nxp.com/t5/Secure-Authentication/X25519-algoritm-doesn-t-generate-the-correct-key/m-p/1011268#M187 <HTML><HEAD></HEAD><BODY><P>I'm having trouble using the X25519 algorithm with the SE050C.</P><P>I've used the example keys from the&nbsp;SE050 APDU Specification (AN 12413), see image.</P><P></P><P><span class="lia-inline-image-display-wrapper" image-alt="derive_ecdh_key_example.png"><img src="https://community.nxp.com/t5/image/serverpage/image-id/72285i49D93F57BB3DD342/image-size/large?v=v2&amp;px=999" role="button" title="derive_ecdh_key_example.png" alt="derive_ecdh_key_example.png" /></span></P><P>According to the given example and the OpenSSL test (in attachments), the shared secret should be:<BR />4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742 (HEX)</P><P></P><P>When I try to derive&nbsp;the shared secret&nbsp;on the SE050C (development kit), I get the wrong key or the operation fails.</P><P>I've used 2 derive functions:</P><UL><LI>sss_derive_key_dh <UL><LI>returns&nbsp;kStatus_SSS_Fail</LI></UL></LI><LI>Se05x_API_ECDHGenerateSharedSecret <UL><LI>returns the wrong key:<BR />68408B1BAA1BDC8EBA074E3A99AEF1B3C94EDFE9F52E60616D1F2A924B2F5D51 (HEX)</LI></UL></LI></UL><P></P><P>Does someone know how to correctly use the X25519 function or can anybody explain what I'm doing wrong? Help is very appreciated.</P><P>I've attached my code and the corresponding output. The code is very similar to the SDK example "ex_sss_ecdh".</P><P>I am using the latest version of&nbsp;SE050-PLUG-TRUST-MW (version 2.12).</P></BODY></HTML> Tue, 14 Jan 2020 16:34:58 GMT jordyubink 2020-01-14T16:34:58Z X25519 algoritm doesn't generate the correct key https://community.nxp.com/t5/Secure-Authentication/X25519-algoritm-doesn-t-generate-the-correct-key/m-p/1011268#M187 <HTML><HEAD></HEAD><BODY><P>I'm having trouble using the X25519 algorithm with the SE050C.</P><P>I've used the example keys from the&nbsp;SE050 APDU Specification (AN 12413), see image.</P><P></P><P><span class="lia-inline-image-display-wrapper" image-alt="derive_ecdh_key_example.png"><img src="https://community.nxp.com/t5/image/serverpage/image-id/72285i49D93F57BB3DD342/image-size/large?v=v2&amp;px=999" role="button" title="derive_ecdh_key_example.png" alt="derive_ecdh_key_example.png" /></span></P><P>According to the given example and the OpenSSL test (in attachments), the shared secret should be:<BR />4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742 (HEX)</P><P></P><P>When I try to derive&nbsp;the shared secret&nbsp;on the SE050C (development kit), I get the wrong key or the operation fails.</P><P>I've used 2 derive functions:</P><UL><LI>sss_derive_key_dh <UL><LI>returns&nbsp;kStatus_SSS_Fail</LI></UL></LI><LI>Se05x_API_ECDHGenerateSharedSecret <UL><LI>returns the wrong key:<BR />68408B1BAA1BDC8EBA074E3A99AEF1B3C94EDFE9F52E60616D1F2A924B2F5D51 (HEX)</LI></UL></LI></UL><P></P><P>Does someone know how to correctly use the X25519 function or can anybody explain what I'm doing wrong? Help is very appreciated.</P><P>I've attached my code and the corresponding output. The code is very similar to the SDK example "ex_sss_ecdh".</P><P>I am using the latest version of&nbsp;SE050-PLUG-TRUST-MW (version 2.12).</P></BODY></HTML> Tue, 14 Jan 2020 16:34:58 GMT https://community.nxp.com/t5/Secure-Authentication/X25519-algoritm-doesn-t-generate-the-correct-key/m-p/1011268#M187 jordyubink 2020-01-14T16:34:58Z