2018-05-15 03:13:16 +00:00
|
|
|
<?xml version="1.0" encoding="UTF-8"?>
|
|
|
|
|
<!DOCTYPE dita PUBLIC "-//OASIS//DTD DITA Composite//EN" "ditabase.dtd">
|
2018-05-15 03:50:14 +00:00
|
|
|
<dita xml:lang="en-GB">
|
2018-05-15 03:13:16 +00:00
|
|
|
<topic id="topic_p3g_yqy_5db">
|
|
|
|
|
<title>Signature Verification</title>
|
|
|
|
|
<body>
|
|
|
|
|
<p>Essentially there are two principal methods of verification of a signature. The first
|
|
|
|
|
of these is for use with the normal or default signing method and for clear-signed messages.
|
|
|
|
|
The second is for use with files and data with detached signatures.</p>
|
|
|
|
|
<p>The following example is intended for use with the default signing method where the file
|
|
|
|
|
was not ASCII armoured:</p>
|
|
|
|
|
<p>
|
|
|
|
|
<codeblock id="verify-1" outputclass="language-python">import gpg
|
|
|
|
|
import time
|
|
|
|
|
|
|
|
|
|
filename = "statement.txt"
|
|
|
|
|
gpg_file = "statement.txt.gpg"
|
|
|
|
|
|
|
|
|
|
c = gpg.Context()
|
|
|
|
|
|
|
|
|
|
try:
|
|
|
|
|
data, result = c.verify(open(gpg_file))
|
|
|
|
|
verified = True
|
|
|
|
|
except gpg.errors.BadSignatures as e:
|
|
|
|
|
verified = False
|
|
|
|
|
print(e)
|
|
|
|
|
|
|
|
|
|
if verified is True:
|
|
|
|
|
for i in range(len(result.signatures)):
|
|
|
|
|
sign = result.signatures[i]
|
|
|
|
|
print("""Good signature from:
|
|
|
|
|
{0}
|
|
|
|
|
with key {1}
|
|
|
|
|
made at {2}
|
|
|
|
|
""".format(c.get_key(sign.fpr).uids[0].uid,
|
|
|
|
|
sign.fpr, time.ctime(sign.timestamp)))
|
|
|
|
|
else:
|
|
|
|
|
pass
|
|
|
|
|
</codeblock>
|
|
|
|
|
</p>
|
|
|
|
|
<p>Whereas this next example, which is almost identical would work with normal ASCII armoured
|
|
|
|
|
files and with clear-signed files:</p>
|
|
|
|
|
<p>
|
|
|
|
|
<codeblock id="verify-2" outputclass="language-python">import gpg
|
|
|
|
|
import time
|
|
|
|
|
|
|
|
|
|
filename = "statement.txt"
|
|
|
|
|
asc_file = "statement.txt.asc"
|
|
|
|
|
|
|
|
|
|
c = gpg.Context()
|
|
|
|
|
|
|
|
|
|
try:
|
|
|
|
|
data, result = c.verify(open(asc_file))
|
|
|
|
|
verified = True
|
|
|
|
|
except gpg.errors.BadSignatures as e:
|
|
|
|
|
verified = False
|
|
|
|
|
print(e)
|
|
|
|
|
|
|
|
|
|
if verified is True:
|
|
|
|
|
for i in range(len(result.signatures)):
|
|
|
|
|
sign = result.signatures[i]
|
|
|
|
|
print("""Good signature from:
|
|
|
|
|
{0}
|
|
|
|
|
with key {1}
|
|
|
|
|
made at {2}
|
|
|
|
|
""".format(c.get_key(sign.fpr).uids[0].uid,
|
|
|
|
|
sign.fpr, time.ctime(sign.timestamp)))
|
|
|
|
|
else:
|
|
|
|
|
pass
|
|
|
|
|
</codeblock>
|
|
|
|
|
</p>
|
|
|
|
|
<p>In both of the previous examples it is also possible to compare the original data that was
|
|
|
|
|
signed against the signed data in <codeph>data</codeph> to see if it matches with something
|
|
|
|
|
like this:</p>
|
|
|
|
|
<p>
|
|
|
|
|
<codeblock id="verify-3" outputclass="language-python">with open(filename, "rb") as afile:
|
|
|
|
|
text = afile.read()
|
|
|
|
|
|
|
|
|
|
if text == data:
|
|
|
|
|
print("Good signature.")
|
|
|
|
|
else:
|
|
|
|
|
pass
|
|
|
|
|
</codeblock>
|
|
|
|
|
</p>
|
|
|
|
|
<p>The following two examples, however, deal with detached signatures. With his method of
|
|
|
|
|
verification the data that was signed does not get returned since it is already being
|
|
|
|
|
explicitly referenced in the first argument of <codeph>c.verify</codeph>. So
|
|
|
|
|
<codeph>data</codeph> is <codeph>None</codeph> and only the information in
|
|
|
|
|
<codeph>result</codeph> is available.</p>
|
|
|
|
|
<p>
|
|
|
|
|
<codeblock id="verify-4" outputclass="language-python">import gpg
|
|
|
|
|
import time
|
|
|
|
|
|
|
|
|
|
filename = "statement.txt"
|
|
|
|
|
sig_file = "statement.txt.sig"
|
|
|
|
|
|
|
|
|
|
c = gpg.Context()
|
|
|
|
|
|
|
|
|
|
try:
|
|
|
|
|
data, result = c.verify(open(filename), open(sig_file))
|
|
|
|
|
verified = True
|
|
|
|
|
except gpg.errors.BadSignatures as e:
|
|
|
|
|
verified = False
|
|
|
|
|
print(e)
|
|
|
|
|
|
|
|
|
|
if verified is True:
|
|
|
|
|
for i in range(len(result.signatures)):
|
|
|
|
|
sign = result.signatures[i]
|
|
|
|
|
print("""Good signature from:
|
|
|
|
|
{0}
|
|
|
|
|
with key {1}
|
|
|
|
|
made at {2}
|
|
|
|
|
""".format(c.get_key(sign.fpr).uids[0].uid,
|
|
|
|
|
sign.fpr, time.ctime(sign.timestamp)))
|
|
|
|
|
else:
|
|
|
|
|
pass
|
|
|
|
|
</codeblock>
|
|
|
|
|
</p>
|
|
|
|
|
<p>
|
|
|
|
|
<codeblock id="verify-5" outputclass="language-python">import gpg
|
|
|
|
|
import time
|
|
|
|
|
|
|
|
|
|
filename = "statement.txt"
|
|
|
|
|
asc_file = "statement.txt.asc"
|
|
|
|
|
|
|
|
|
|
c = gpg.Context()
|
|
|
|
|
|
|
|
|
|
try:
|
|
|
|
|
data, result = c.verify(open(filename), open(asc_file))
|
|
|
|
|
verified = True
|
|
|
|
|
except gpg.errors.BadSignatures as e:
|
|
|
|
|
verified = False
|
|
|
|
|
print(e)
|
|
|
|
|
|
|
|
|
|
if verified is not None:
|
|
|
|
|
for i in range(len(result.signatures)):
|
|
|
|
|
sign = result.signatures[i]
|
|
|
|
|
print("""Good signature from:
|
|
|
|
|
{0}
|
|
|
|
|
with key {1}
|
|
|
|
|
made at {2}
|
|
|
|
|
""".format(c.get_key(sign.fpr).uids[0].uid,
|
|
|
|
|
sign.fpr, time.ctime(sign.timestamp)))
|
|
|
|
|
else:
|
|
|
|
|
pass
|
|
|
|
|
</codeblock>
|
|
|
|
|
</p>
|
|
|
|
|
</body>
|
|
|
|
|
</topic>
|
|
|
|
|
</dita>
|
