Opc.Ua.RsaUtils.RsaPkcs15Sha256_Verify C# (CSharp) Method

        public static bool RsaPkcs15Sha256_Verify(
            ArraySegment<byte> dataToVerify,
            byte[] signature,
            X509Certificate2 signingCertificate)
        {
            // extract the private key.
            using (RSA rsa = signingCertificate.GetRSAPublicKey())
            {

                if (rsa == null)
                {
                    throw ServiceResultException.Create(StatusCodes.BadSecurityChecksFailed, "No public key for certificate.");
                }

                // verify signature.
                return rsa.VerifyData(dataToVerify.Array, dataToVerify.Offset, dataToVerify.Count, signature, HashAlgorithmName.SHA256, RSASignaturePadding.Pkcs1);
            }
        }

        /// <summary>
        /// Verifies the signature using the SecurityPolicyUri and return true if valid.
        /// </summary>
        public static bool Verify(X509Certificate2 certificate, string securityPolicyUri, byte[] dataToVerify, SignatureData signature)
        {
            // check if nothing to do.
            if (signature == null)
            {
                return(true);
            }

            // nothing more to do if no encryption.
            if (String.IsNullOrEmpty(securityPolicyUri))
            {
                return(true);
            }

            // decrypt data.
            switch (securityPolicyUri)
            {
            case SecurityPolicies.Basic256:
            case SecurityPolicies.Basic128Rsa15:
            {
                if (signature.Algorithm == SecurityAlgorithms.RsaSha1)
                {
                    return(RsaUtils.RsaPkcs15Sha1_Verify(new ArraySegment <byte>(dataToVerify), signature.Signature, certificate));
                }

                break;
            }

            case SecurityPolicies.Basic256Sha256:
            {
                if (signature.Algorithm == SecurityAlgorithms.RsaSha256)
                {
                    return(RsaUtils.RsaPkcs15Sha256_Verify(new ArraySegment <byte>(dataToVerify), signature.Signature, certificate));
                }

                break;
            }

            // always accept signatures if security is not used.
            case SecurityPolicies.None:
            {
                return(true);
            }

            default:
            {
                throw ServiceResultException.Create(
                          StatusCodes.BadSecurityPolicyRejected,
                          "Unsupported security policy: {0}",
                          securityPolicyUri);
            }
            }

            throw ServiceResultException.Create(
                      StatusCodes.BadSecurityChecksFailed,
                      "Unexpected signature algorithm : {0}",
                      signature.Algorithm);
        }