Added pytss python tutorials (quote)

PythonExamples/README.md

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+# Python Examples with PYTSS
+
+Now that tpm2_pytss is stable I've started collecting worked examples for some common situations, eg: reading PCRs, quotes etc.
+
+tpm_pytss is here: https://github.com/tpm2-software/tpm2-pytss
+
+## Running the examples
+
+First you will need a TPM, either a real TPM or the IBM SW TPM is a good substitute.
+
+Each example can be run just by typing `python3 example.py`
+
+## Available Examples
+
+Each example has an accompanying description as markdown file, plus annotated code.
+
+   * [quote]

PythonExamples/quote.md

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+# Quote
+
+This example demonstrates the use of ESAPI.quote
+
+The code will:
+
+   * setup the ESAPI interface
+   * send a TPM_STARTUP clear command
+   * request a quote using the given attestation key, pcrs and extradata
+   * unmarshal the returned data structures and print these as a python dict and convert to JSON and pretty print
+
+## Setup and Variables
+
+The following code might need to be modified for you local setup
+
+```python3
+tcti_to_use = None
+attestation_key_handle = 0x810100AA
+pcrs_to_quote = "sha256:0,1,2,3"
+extradata_to_use = b"Ian12345"
+```
+
+## Running
+
+To run type `python3 quote.py`
+
+Errors might be generated as the pytss libraries search for a suitable TPM device. If everything is successful then a pretty printed JSON structure will be shown.
+
+## Example Output
+
+```bash
+~/tpm.dev.tutorials/PythonExamples$ python3 quote.py 
+ERROR:tcti:src/tss2-tcti/tcti-device.c:442:Tss2_Tcti_Device_Init() Failed to open specified TCTI device file /dev/tpmrm0: No such file or directory 
+ERROR:tcti:src/tss2-tcti/tctildr-dl.c:154:tcti_from_file() Could not initialize TCTI file: libtss2-tcti-device.so.0 
+ERROR:tcti:src/tss2-tcti/tcti-device.c:442:Tss2_Tcti_Device_Init() Failed to open specified TCTI device file /dev/tpm0: No such file or directory 
+ERROR:tcti:src/tss2-tcti/tctildr-dl.c:154:tcti_from_file() Could not initialize TCTI file: libtss2-tcti-device.so.0 
+ERROR:tcti:src/tss2-tcti/tcti-swtpm.c:222:tcti_control_command() Control command failed with error: 1 
+ERROR:tcti:src/tss2-tcti/tcti-swtpm.c:330:tcti_swtpm_set_locality() Failed to set locality: 0xa000a 
+WARNING:tcti:src/tss2-tcti/tcti-swtpm.c:599:Tss2_Tcti_Swtpm_Init() Could not set locality via control channel: 0xa000a 
+ERROR:tcti:src/tss2-tcti/tctildr-dl.c:154:tcti_from_file() Could not initialize TCTI file: libtss2-tcti-swtpm.so.0 
+att= <tpm2_pytss.types.TPMS_ATTEST object at 0x7f5fb10419d0>
+ae= <class 'dict'> 
+ {'attested': {'pcrDigest': '38723a2e5e8a17aa7950dc008209944e898f69a7bd10a23c839d341e935fd5ca', 'pcrSelect': [{'hash': 'sha256', 'pcrSelect': [0, 1, 2, 3]}]}, 'clockInfo': {'clock': 308418200, 'resetCount': 22, 'restartCount': 0, 'safe': 1}, 'extraData': '49616e3132333435', 'firmwareVersion': [538513443, 1455670], 'magic': 4283712327, 'qualifiedSigner': '000bff3ea118be81e7f10ead098c900b93c885785e828bf27d824a87add847b5ec56', 'type': 'attest_quote'}
+
+ {
+    "attested": {
+        "pcrDigest": "38723a2e5e8a17aa7950dc008209944e898f69a7bd10a23c839d341e935fd5ca",
+        "pcrSelect": [
+            {
+                "hash": "sha256",
+                "pcrSelect": [
+                    0,
+                    1,
+                    2,
+                    3
+                ]
+            }
+        ]
+    },
+    "clockInfo": {
+        "clock": 308418200,
+        "resetCount": 22,
+        "restartCount": 0,
+        "safe": 1
+    },
+    "extraData": "49616e3132333435",
+    "firmwareVersion": [
+        538513443,
+        1455670
+    ],
+    "magic": 4283712327,
+    "qualifiedSigner": "000bff3ea118be81e7f10ead098c900b93c885785e828bf27d824a87add847b5ec56",
+    "type": "attest_quote"
+}
+
+```

PythonExamples/quote.py

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+#
+# Import the tpm2_pytss libraries and the encoders
+#
+
+from tpm2_pytss import *
+from tpm2_pytss.encoding import (
+    base_encdec,
+    json_encdec,
+)
+
+#
+# We also need this too, for convenience later
+#
+
+import json
+
+#
+# Setting up some variables here for convenience
+#
+
+tcti_to_use = None
+attestation_key_handle = 0x810100AA
+pcrs_to_quote = "sha256:0,1,2,3"
+extradata_to_use = b"Ian12345"
+
+#
+# Make a connection to a TPM and use the ESAPI interface
+# tcti=None means that the pytss libraries will search for an available TCTI
+#
+#
+# When this is run, then as the various TCTI interfaces are searched errors are written if those interfaces are not foud
+#
+
+tpm = ESAPI(tcti=None)
+
+# 
+# Send a startup message, just in case (actually this is because I'm using the IBM SW TPM and haven't started it properly)
+#
+
+tpm.startup(TPM2_SU.CLEAR)
+
+#
+# Create the necessary parameters for making a quote
+#
+
+
+handle =  tpm.tr_from_tpmpublic(attestation_key_handle)
+pcrsels = TPML_PCR_SELECTION.parse(pcrs_to_quote)
+extradata_to_use = TPM2B_DATA(extradata_to_use)
+
+#
+# Now to make the quote and return the attested values and signature
+#
+
+quote,signature = tpm.quote(
+	  handle, pcrsels, extradata_to_use
+	)
+
+#
+# Now to unmarshal the attested values and we'll print them out which'll give a tpm2_pytss.types.TPMS_ATTEST object
+#
+
+att,_ = TPMS_ATTEST.unmarshal( bytes(quote) )
+print("att=",att)
+
+#
+# We construct an encoder and encode that structure in a python dict
+#
+
+enc = json_encdec() 
+ae = enc.encode(att)
+print("ae=",type(ae),"\n",ae)
+
+#
+# Now we'll use the json library to convert that to JSON and pretty print it
+#
+
+js = json.dumps(ae,indent=4)
+print("\n",js)