diff --git a/src/System.Net.TestData/TestDataCertificates/contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/contoso.com.pfx
index c2fcf19856..564fe7c1e9 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testclient1_at_contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testclient1_at_contoso.com.pfx
index a86fc5dc4b..180182ecac 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testclient1_at_contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testclient1_at_contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testclienteku.contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testclienteku.contoso.com.pfx
index fbebfb015f..6a49bc877d 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testclienteku.contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testclienteku.contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testnoeku.contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testnoeku.contoso.com.pfx
index d65da8750e..b43288263f 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testnoeku.contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testnoeku.contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testselfsignedclienteku.contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testselfsignedclienteku.contoso.com.pfx
index e5779670c5..6a397a0c1a 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testselfsignedclienteku.contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testselfsignedclienteku.contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testselfsignedservereku.contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testselfsignedservereku.contoso.com.pfx
index 49f85f1e17..ddbc084ac9 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testselfsignedservereku.contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testselfsignedservereku.contoso.com.pfx differ
diff --git a/src/System.Net.TestData/TestDataCertificates/testservereku.contoso.com.pfx b/src/System.Net.TestData/TestDataCertificates/testservereku.contoso.com.pfx
index 1b6111f731..936e289831 100644
Binary files a/src/System.Net.TestData/TestDataCertificates/testservereku.contoso.com.pfx and b/src/System.Net.TestData/TestDataCertificates/testservereku.contoso.com.pfx differ
diff --git a/src/System.Net.TestData/readme.md b/src/System.Net.TestData/readme.md
new file mode 100644
index 0000000000..e03aab3da5
--- /dev/null
+++ b/src/System.Net.TestData/readme.md
@@ -0,0 +1,7 @@
+# System.Net test certificates
+
+This package contains test certificates for `System.Net` library.
+
+The TestData directory is considered obsolete. The certificates are encrypted with RC2 and triple des encryption. The pfx password is `testcertificate`.
+
+The TestDataCertificates directory contains the same pfx certificates as in TestData however they are all encrypted by triple des encryption. The pfx password is `PLACEHOLDER`.
\ No newline at end of file