diff --git a/src/libraries/System.Net.Http.WinHttpHandler/tests/UnitTests/ClientCertificateHelper.cs b/src/libraries/System.Net.Http.WinHttpHandler/tests/UnitTests/ClientCertificateHelper.cs
index b0e144992937c4..d59febe8bca931 100644
--- a/src/libraries/System.Net.Http.WinHttpHandler/tests/UnitTests/ClientCertificateHelper.cs
+++ b/src/libraries/System.Net.Http.WinHttpHandler/tests/UnitTests/ClientCertificateHelper.cs
@@ -13,6 +13,7 @@ public class ClientCertificateHelper
         private readonly X509Certificate2 _cert_KeyUsageIncludesDigitalSignature_EKUIncludesClientAuth_PrivateKey =
             new X509Certificate2(
                 Convert.FromBase64String(
+                  // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Unit test dummy certificate.")]
                   @"MIIKTgIBAzCCCgoGCSqGSIb3DQEHAaCCCfsEggn3MIIJ8zCCBgwGCSqGSIb3DQEHAaCCBf0EggX5
                     MIIF9TCCBfEGCyqGSIb3DQEMCgECoIIE/jCCBPowHAYKKoZIhvcNAQwBAzAOBAiHDatvDr8QBQIC
                     B9AEggTYv1r4ckwt7o6f6DCMHlb/zv4t7rPju+PP0PjoJ8kzPfj419aSeyPuE+65YH9WFDqafJed
@@ -65,6 +66,7 @@ public class ClientCertificateHelper
         private readonly X509Certificate2 _cert_KeyUsageMissingDigitalSignature_EKUIncludesClientAuth_PrivateKey =
             new X509Certificate2(
                 Convert.FromBase64String(
+                   // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Unit test dummy certificate.")]
                   @"MIIKTgIBAzCCCgoGCSqGSIb3DQEHAaCCCfsEggn3MIIJ8zCCBgwGCSqGSIb3DQEHAaCCBf0EggX5
                     MIIF9TCCBfEGCyqGSIb3DQEMCgECoIIE/jCCBPowHAYKKoZIhvcNAQwBAzAOBAiSNi65ZF5ZTQIC
                     B9AEggTYRTivDtzHOWRR+MobtGFEUu6d1PiIlF1Ic84FWvmFCcJShkBmg3cBqDilqtamAkDkga4h
@@ -117,6 +119,7 @@ public class ClientCertificateHelper
         private readonly X509Certificate2 _cert_KeyUsageIncludesDigitalSignature_EKUMissingClientAuth_PrivateKey =
             new X509Certificate2(
                 Convert.FromBase64String(
+                   // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                   @"MIIKRgIBAzCCCgIGCSqGSIb3DQEHAaCCCfMEggnvMIIJ6zCCBgQGCSqGSIb3DQEHAaCCBfUEggXx
                     MIIF7TCCBekGCyqGSIb3DQEMCgECoIIE9jCCBPIwHAYKKoZIhvcNAQwBAzAOBAhCUuNQ0RqfZQIC
                     B9AEggTQHCQRSiCiNI7egTvUaI1Z3tfeLwFWvG7B/za5v9fb97MExoyVQSDmUyUDTlVEcg3gVqJZ
@@ -169,6 +172,7 @@ public class ClientCertificateHelper
         private readonly X509Certificate2 _cert_KeyUsageIncludesDigitalSignature_NoEKU_PrivateKey =
             new X509Certificate2(
                 Convert.FromBase64String(
+                   // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                   @"MIIKPgIBAzCCCfoGCSqGSIb3DQEHAaCCCesEggnnMIIJ4zCCBgwGCSqGSIb3DQEHAaCCBf0EggX5
                     MIIF9TCCBfEGCyqGSIb3DQEMCgECoIIE/jCCBPowHAYKKoZIhvcNAQwBAzAOBAijQh1kbOZOYQIC
                     B9AEggTY+wDp3V31Lh7f8YrsqEsyGZ+GlYvFhLWvDASjisYJi5NlQ0ONbf0KOXHVSvBj3tVyuHm4
@@ -221,6 +225,7 @@ public class ClientCertificateHelper
         private readonly X509Certificate2 _cert_KeyUsageIncludesDigitalSignature_EKUIncludesClientAuth_NoPrivateKey =
             new X509Certificate2(
                 Convert.FromBase64String(
+                   // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                   @"MIIDFjCCAf6gAwIBAgIQTm8+EF94L4FJ0nBFl5LICzANBgkqhkiG9w0BAQsFADAb
                     MRkwFwYDVQQDDBB1c2VyQGV4YW1wbGUuY29tMCAXDTE1MTAwNTEwMDMwMFoYDzIx
                     MTUxMDA1MTAwMzAwWjAbMRkwFwYDVQQDDBB1c2VyQGV4YW1wbGUuY29tMIIBIjAN
diff --git a/src/libraries/System.Security.Cryptography.Pkcs/tests/Certificates.cs b/src/libraries/System.Security.Cryptography.Pkcs/tests/Certificates.cs
index 028defaf5eafda..fb95bd9e36387d 100644
--- a/src/libraries/System.Security.Cryptography.Pkcs/tests/Certificates.cs
+++ b/src/libraries/System.Security.Cryptography.Pkcs/tests/Certificates.cs
@@ -1996,6 +1996,7 @@ private static class RawData
                     : TlsClientServerEkuPfx_TripleDESContentEncryption;
 
             internal static readonly byte[] s_RSAKeyTransfer4_ExplicitSkiCer = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURhakNDQWxLZ0F3SUJBZ0lKQUppdWpocnpi" +
                 "Sk9XTUEwR0NTcUdTSWIzRFFFQkN3VUFNR014Q3pBSkJnTlYKQkFZVEFsVlRNUk13RVFZRFZRUUlE" +
                 "QXBYWVhOb2FXNW5kRzl1TVJBd0RnWURWUVFIREFkU1pXUnRiMjVrTVJJdwpFQVlEVlFRS0RBbE5h" +
@@ -2020,6 +2021,7 @@ private static class RawData
                 "ClEveU9MN2psMGFnT1dTcngwWnM9Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K");
 
             private static readonly byte[] s_RSAKeyTransfer4_ExplicitSkiPfx_RC2ContentEncryption = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "MIIJqQIBAzCCCW8GCSqGSIb3DQEHAaCCCWAEgglcMIIJWDCCBA8GCSqGSIb3DQEHBqCCBAAwggP8" +
                 "AgEAMIID9QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQI2rQEBhq4HAUCAggAgIIDyEn+zCF3" +
                 "wteqkmcbOFO7Aa2HbI8d1Dbp8M2QESYZhIZr/nX69etCuh4UewErHwwxfJYVQjhKO9NhWO4wB3UP" +
@@ -2066,6 +2068,7 @@ private static class RawData
                 "sbfisMs0Ll8CgjH2BAhMwg4eZANcOgICCAA=");
 
             private static readonly byte[] s_RSAKeyTransfer4_ExplicitSkiPfx_TripleDESContentEncryption = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "MIIJuwIBAzCCCXcGCSqGSIb3DQEHAaCCCWgEgglkMIIJYDCCBBcGCSqGSIb3DQEHBqCCBAgwggQE" +
                 "AgEAMIID/QYJKoZIhvcNAQcBMCQGCiqGSIb3DQEMAQMwFgQQzMqKF6TLC64Jd+DF7mgQmQICB9CA" +
                 "ggPIoCkOExBhWQ0rnLj6ZlwP9pkKhnC07NHHXBuRKQTLdZgQlchqjz6wMebmc+ZlwVQbaPvJmXMF" +
@@ -2117,6 +2120,7 @@ private static class RawData
                     : s_RSAKeyTransfer4_ExplicitSkiPfx_TripleDESContentEncryption;
 
             internal static readonly byte[] s_RSAKeyTransfer5_ExplicitSkiOfRSAKeyTransfer4Cer = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSURhakNDQWxLZ0F3SUJBZ0lKQUs0cjJQai96" +
                 "ZnF2TUEwR0NTcUdTSWIzRFFFQkN3VUFNR014Q3pBSkJnTlYKQkFZVEFsVlRNUk13RVFZRFZRUUlE" +
                 "QXBYWVhOb2FXNW5kRzl1TVJBd0RnWURWUVFIREFkU1pXUnRiMjVrTVJJdwpFQVlEVlFRS0RBbE5h" +
@@ -2141,6 +2145,7 @@ private static class RawData
                 "CkZDUFYveUJyVm5Md0ZHR3NheFk9Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K");
 
             private static readonly byte[] s_RSAKeyTransfer5_ExplicitSkiOfRSAKeyTransfer4Pfx_RC2ContentEncryption = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "MIIJqQIBAzCCCW8GCSqGSIb3DQEHAaCCCWAEgglcMIIJWDCCBA8GCSqGSIb3DQEHBqCCBAAwggP8" +
                 "AgEAMIID9QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQITLms5nr095wCAggAgIIDyPyxib5c" +
                 "oCEPC3OpfmCzzieARKf56sQZU31qlDJNDet7v1R68T7X9vu236kHOphKvqedPVNXKEPpaQXIxkSY" +
@@ -2187,6 +2192,7 @@ private static class RawData
                 "f0PE6idyhcH963CyBAiMLpuBSuzCdgICCAA=");
 
             private static readonly byte[] s_RSAKeyTransfer5_ExplicitSkiOfRSAKeyTransfer4Pfx_TripleDESContentEncryption = Convert.FromBase64String(
+                // [SuppressMessage("Microsoft.Security", "CS002:SecretInNextLine", Justification="Suppression approved. Dummy certificate for testing.")]
                 "MIIJuwIBAzCCCXcGCSqGSIb3DQEHAaCCCWgEgglkMIIJYDCCBBcGCSqGSIb3DQEHBqCCBAgwggQE" +
                 "AgEAMIID/QYJKoZIhvcNAQcBMCQGCiqGSIb3DQEMAQMwFgQQcikkI3mNYPzp9KgATYd+sgICB9CA" +
                 "ggPI8jMlpeNA98igwqedfn4BlSDksVxqex+KPgGDn/UYx/S5yfQMUxq2vocr3mXGBGm5B7/4v7mV" +
