151 lines
4.1 KiB
Plaintext
151 lines
4.1 KiB
Plaintext
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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE dita PUBLIC "-//OASIS//DTD DITA Composite//EN" "ditabase.dtd">
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<dita>
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<topic id="topic_p3g_yqy_5db">
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<title>Signature Verification</title>
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<body>
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<p>Essentially there are two principal methods of verification of a signature. The first
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of these is for use with the normal or default signing method and for clear-signed messages.
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The second is for use with files and data with detached signatures.</p>
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<p>The following example is intended for use with the default signing method where the file
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was not ASCII armoured:</p>
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<p>
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<codeblock id="verify-1" outputclass="language-python">import gpg
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import time
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filename = "statement.txt"
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gpg_file = "statement.txt.gpg"
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c = gpg.Context()
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try:
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data, result = c.verify(open(gpg_file))
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verified = True
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except gpg.errors.BadSignatures as e:
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verified = False
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print(e)
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if verified is True:
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for i in range(len(result.signatures)):
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sign = result.signatures[i]
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print("""Good signature from:
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{0}
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with key {1}
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made at {2}
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""".format(c.get_key(sign.fpr).uids[0].uid,
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sign.fpr, time.ctime(sign.timestamp)))
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else:
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pass
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</codeblock>
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</p>
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<p>Whereas this next example, which is almost identical would work with normal ASCII armoured
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files and with clear-signed files:</p>
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<p>
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<codeblock id="verify-2" outputclass="language-python">import gpg
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import time
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filename = "statement.txt"
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asc_file = "statement.txt.asc"
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c = gpg.Context()
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try:
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data, result = c.verify(open(asc_file))
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verified = True
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except gpg.errors.BadSignatures as e:
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verified = False
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print(e)
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if verified is True:
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for i in range(len(result.signatures)):
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sign = result.signatures[i]
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print("""Good signature from:
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{0}
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with key {1}
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made at {2}
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""".format(c.get_key(sign.fpr).uids[0].uid,
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sign.fpr, time.ctime(sign.timestamp)))
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else:
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pass
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</codeblock>
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</p>
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<p>In both of the previous examples it is also possible to compare the original data that was
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signed against the signed data in <codeph>data</codeph> to see if it matches with something
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like this:</p>
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<p>
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<codeblock id="verify-3" outputclass="language-python">with open(filename, "rb") as afile:
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text = afile.read()
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if text == data:
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print("Good signature.")
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else:
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pass
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</codeblock>
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</p>
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<p>The following two examples, however, deal with detached signatures. With his method of
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verification the data that was signed does not get returned since it is already being
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explicitly referenced in the first argument of <codeph>c.verify</codeph>. So
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<codeph>data</codeph> is <codeph>None</codeph> and only the information in
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<codeph>result</codeph> is available.</p>
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<p>
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<codeblock id="verify-4" outputclass="language-python">import gpg
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import time
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filename = "statement.txt"
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sig_file = "statement.txt.sig"
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c = gpg.Context()
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try:
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data, result = c.verify(open(filename), open(sig_file))
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verified = True
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except gpg.errors.BadSignatures as e:
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verified = False
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print(e)
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if verified is True:
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for i in range(len(result.signatures)):
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sign = result.signatures[i]
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print("""Good signature from:
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{0}
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with key {1}
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made at {2}
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""".format(c.get_key(sign.fpr).uids[0].uid,
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sign.fpr, time.ctime(sign.timestamp)))
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else:
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pass
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</codeblock>
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</p>
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<p>
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<codeblock id="verify-5" outputclass="language-python">import gpg
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import time
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filename = "statement.txt"
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asc_file = "statement.txt.asc"
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c = gpg.Context()
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try:
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data, result = c.verify(open(filename), open(asc_file))
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verified = True
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except gpg.errors.BadSignatures as e:
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verified = False
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print(e)
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if verified is not None:
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for i in range(len(result.signatures)):
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sign = result.signatures[i]
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print("""Good signature from:
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{0}
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with key {1}
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made at {2}
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""".format(c.get_key(sign.fpr).uids[0].uid,
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sign.fpr, time.ctime(sign.timestamp)))
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else:
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pass
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</codeblock>
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</p>
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</body>
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</topic>
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</dita>
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