Erase other identical phrases

[estevopaz]

import SecureString

secret = 'foo'
secret_2 = secret
secret_3 = 'foo'

SecureString.clearmem(secret)

print('Secret: ' + secret)
print('Secret copy: ' + secret_2)
print('New identical secret: ' + secret_3)

Output:

Secret: 
Secret copy: 
New identical secret: 

secret_3 is also erased despite no called to erase.
I understand that python (3.6 in my case) reuse memory for identical phrases,
so probably we must live with this.

So I open this issue only to confirm if some solution is possible or not, thanks a lot ;)

[dnet]

You're right, unfortunately this project breaks some core assumptions within the Python VM. Mind you, this only affects string literals defined in the source code, whether defined directly or in a way that could be computed easily. So when used for that sole really important task of erasing cryptographic secrets, this shouldn't cause any problems.

See this example below:

>>> a = 'foo'
>>> b = 'foo'
>>> id(a), id(b)
(140562558659400, 140562558659400)
>>> c = 'fo' + 'o'
>>> id(c)
140562558659400
>>> c = a[:1] + b[1:]
>>> id(c)
140562558659560