I'm trying to sign data in C#, using ECDSA algorithm (this part looks OK) and to verify signature in C using Windows crypto API. Signature part: CngKeyCreationParameters keyCreationParameters = new CngKeyCreationParameters(); keyCreationParameters.ExportPolicy = CngExportPolicies.AllowPlaintextExport; keyCreationParameters.KeyUsage = CngKeyUsages.Signing; CngKey key = CngKey.Create(CngAlgorithm.ECDsaP256, null, keyCreationParameters); ECDsaCng dsa = new ECDsaCng(key); //dsa = [...] read more