The way I think you are trying it in Reader won't give you want you need. If you want to hide the data in the XML email submission (from email submit button), you need the newer capabilities in Designer 10.x to encrypt the submission. The XML contents will look like this after it is encrypted:
<?xml version="1.0" encoding="UTF-8"?>
<xfa:data xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/"
><EncryptedData xmlns="http://www.w3.org/2001/04/xmlenc#" Id="encrypteddata_2" Type="http://www.w3.org/2001/04/xmlenc#Element"
><EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes256-cbc"
/><KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#"
><EncryptedKey xmlns="http://www.w3.org/2001/04/xmlenc#"
><EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5"
/><KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#"
><X509Data
><X509Certificate
>MIICRTCCAa6gAwIBAgIKNvzDsAiaeyPYFDANBgkqhkiG9w0BAQUFADBTMREwDwYDVQQDE whKb2hu
IERvZTEJMAcGA1UEChMAMQkwBwYDVQQLEwAxGzAZBgkqhkiG9w0BCQEWDGpkb2VAYWJjLm NvbTEL
MAkGA1UEBhMCVVMwHhcNMTExMTAzMjA1MjAwWhcNMTYxMTAzMjA1MjAwWjBTMREwDwYDVQ QDEwhK
b2huIERvZTEJMAcGA1UEChMAMQkwBwYDVQQLEwAxGzAZBgkqhkiG9w0BCQEWDGpkb2VAYW JjLmNv
bTELMAkGA1UEBhMCVVMwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAL12YAntp+1Zzs Npew5H
+s5fwLjK3TdiFfMrJuV1jEG2xlvJPOvKujSeR+4iHlBTQbYxkZ5nvhkwQi9KDgeriuMjg/ TclkJP
CD0h//4fnP4tQqTUAZ92r6nMRqFxviEhysETMQl01SGDUlmSjhvWJctPU+krq+wwuwVbPJ gU8Iu5
AgMBAAGjIDAeMA8GCSqGSIb3LwEBCgQCBQAwCwYDVR0PBAQDAgSQMA0GCSqGSIb3DQEBBQ UAA4GB
AK+TIhyZZtYtxrVz5lq/zl8mczRnUCsJcapXJhY/oJnN2izALPAYnA4eBr7LBbl1Hf12op +LJuoU
j5FHhB+eQzKlhqkC/alFwmGdxCBYUfpZKWGBUuuW+00mTCStsmTIaSi/XS6K+Y5+0fqAJ4 8y56lb
o/kjbxSjzHWszfeOzafF</X509Certificate
></X509Data
></KeyInfo
><CipherData
><CipherValue
>ADk2Kxut+M84Pi4B1ZC9znKFCz2rAfHYZNZ76fWK/eRE5QMC0NhCnQ5gFfrOLU9Wl/5FO TZMwQab
F1PjdKaVys0TjOR51HH1A6D/ZUf7baBQ1XnKRW5kQR8xePwwDaRoyBopF8+XeWA6d8yRXv yZdLJa
Hju2/gUR/M2HArKCtso=</CipherValue
></CipherData
></EncryptedKey
></KeyInfo
><CipherData
><CipherValue
>uiKSewcq2Of8cIk7hRnjFmOpTo+XxN6AZM5PyT+k2d1mUuBlbJWxCk37EFiwVHRH5n4oO QkuFFhv
+jopOPQLbthkdhiDzWHmAJhstaPcbvA=</CipherValue
></CipherData
><EncryptionProperties
><EncryptionProperty xfa:processingRule="replacementContent"
><form1
/></EncryptionProperty
></EncryptionProperties
></EncryptedData
><signatures
><Signature xmlns="http://www.w3.org/2000/09/xmldsig#" Id="datasignature_2"
><SignedInfo
><CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#WithComments"
/><SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"
/><Reference URI="#idbfea09cc-7f34-11e1-9c29-002710682eb5" Type="http://www.w3.org/2000/09/xmldsig#SignatureProperties"
><Transforms
><Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#WithComments"
/></Transforms
><DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"
/><DigestValue
>O9E5XR6E+tkicSPa6HTZgkE9qhE=</DigestValue
></Reference
><Reference URI=""
><Transforms
><Transform Algorithm="http://www.w3.org/2002/06/xmldsig-filter2"
><XPath xmlns="http://www.w3.org/2002/06/xmldsig-filter2" xmlns:dsig="http://www.w3.org/2000/09/xmldsig#" Filter="intersect"
>here()/ancestor::dsig:Signature[1]/../..//. |
here()/ancestor::dsig:Signature[1]/../..//@* |
here()/ancestor::dsig:Signature[1]/../..//namespace::*</XPath
></Transform
><Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"
/><Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#WithComments"
/></Transforms
><DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"
/><DigestValue
>v9suUKmCN2M3JeTTr2y5/L6ZY64=</DigestValue
></Reference
></SignedInfo
><SignatureValue
>DYCW4mlxVOr+EmleCo56aohSGw93gtk2Wc5Rb7zlB8ukTSC9lozQM1rGLv4GykpQ+Ln+X hKCzVqv
Z7jcISv2l+1rWWpBSyhve+szoWSoY90SEtPUwnJMwxeOy6fOyGx5MWCqVj6D308Pcu2dw7 r3UMqc
i6rSWUezvsPjfCBrcW8=</SignatureValue
><KeyInfo
><X509Data
><X509Certificate
>MIICRTCCAa6gAwIBAgIKNvzDsAiaeyPYFDANBgkqhkiG9w0BAQUFADBTMREwDwYDVQQDE whKb2hu
IERvZTEJMAcGA1UEChMAMQkwBwYDVQQLEwAxGzAZBgkqhkiG9w0BCQEWDGpkb2VAYWJjLm NvbTEL
MAkGA1UEBhMCVVMwHhcNMTExMTAzMjA1MjAwWhcNMTYxMTAzMjA1MjAwWjBTMREwDwYDVQ QDEwhK
b2huIERvZTEJMAcGA1UEChMAMQkwBwYDVQQLEwAxGzAZBgkqhkiG9w0BCQEWDGpkb2VAYW JjLmNv
bTELMAkGA1UEBhMCVVMwgZ8wDQYJKoZIhvcNAQEBBQADgY0AMIGJAoGBAL12YAntp+1Zzs Npew5H
+s5fwLjK3TdiFfMrJuV1jEG2xlvJPOvKujSeR+4iHlBTQbYxkZ5nvhkwQi9KDgeriuMjg/ TclkJP
CD0h//4fnP4tQqTUAZ92r6nMRqFxviEhysETMQl01SGDUlmSjhvWJctPU+krq+wwuwVbPJ gU8Iu5
AgMBAAGjIDAeMA8GCSqGSIb3LwEBCgQCBQAwCwYDVR0PBAQDAgSQMA0GCSqGSIb3DQEBBQ UAA4GB
AK+TIhyZZtYtxrVz5lq/zl8mczRnUCsJcapXJhY/oJnN2izALPAYnA4eBr7LBbl1Hf12op +LJuoU
j5FHhB+eQzKlhqkC/alFwmGdxCBYUfpZKWGBUuuW+00mTCStsmTIaSi/XS6K+Y5+0fqAJ4 8y56lb
o/kjbxSjzHWszfeOzafF</X509Certificate
></X509Data
></KeyInfo
><Object
><SignatureProperties Id="idbfea09cc-7f34-11e1-9c29-002710682eb5"
><SignatureProperty Target="datasignature_2"
><PROP_Sig xmlns="http://ns.adobe.com/pdf/2006" type="cabinet"
><M type="text"
>D:20120405113353-04'00'</M
><Name type="text"
>John</Name
></PROP_Sig
></SignatureProperty
></SignatureProperties
></Object
></Signature
></signatures
></xfa:data
>
In the Designer version you have (8.2), you only have the capability to sign the data or the entire form, which will not hide its values in the XML file that gets sent.
