CODEWITHSUNDEEP
pythonrsa
user6556957
user6556957

Reputation: 205

python "RSA key format is not supported" when reading from .pem file

Here is my code:

from Crypto.PublicKey import RSA

#Write key to file
key = RSA.generate(4096)
privateKey = key.exportKey()
file1 = open('keyfile.pem', 'wb')
file1.write(privateKey)
file1.close()

#Read key from file
file2 = open('keyfile.pem', 'rb')
key = RSA.importKey(file2.read()) #this is the problem

The error is "RSA key format is not supported." Can anyone help me with the best way to write/read the private key from a file?

Upvotes: 8

Views: 31106

Answers (2)

Anagnostou John
Anagnostou John

Reputation: 514

My answer and a little more complicated with pair of keys

from Crypto.PublicKey import RSA
key = RSA.generate(4096)
f = open('/home/john/Desktop/my_rsa_public.pem', 'wb')
f.close()
f.write(key.publickey().exportKey('PEM'))
f = open('/home/john/Desktop/my_rsa_private.pem', 'wb')
f.write(key.exportKey('PEM'))
f.close()

f = open('/home/john/Desktop/my_rsa_public.pem', 'rb')
f1 = open('/home/john/Desktop/my_rsa_private.pem', 'rb')
key = RSA.importKey(f.read())
key1 = RSA.importKey(f1.read())

x = key.encrypt(b"dddddd",32)

print(x)
z = key1.decrypt(x)
print(z)

Upvotes: 6

l'L'l
l'L'l

Reputation: 47264

You have multiple issues with your code, mainly the way you are reading and writing the key. You never close the file, then open it twice during your read function; try changing your code to:

#Write key to file
key = RSA.generate(4096)
f = open('keyfile.pem', 'wb')
f.write(key.exportKey('PEM'))
f.close()

#Read key from file
f = open('keyfile.pem', 'rb')
key = RSA.importKey(f.read())

Result:

<_RSAobj @0x10d3cb2d8 n(4096),e,d,p,q,u,private>

Upvotes: 3

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