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diff --git a/pipermail/pycrypto/2009q1/000067.html b/pipermail/pycrypto/2009q1/000067.html new file mode 100644 index 0000000..30cbc96 --- /dev/null +++ b/pipermail/pycrypto/2009q1/000067.html @@ -0,0 +1,178 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML> + <HEAD> + <TITLE> [pycrypto] PyCrypto AND Crypt_RSA integration + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:pycrypto%40lists.dlitz.net?Subject=%5Bpycrypto%5D%20PyCrypto%20AND%20Crypt_RSA%20integration&In-Reply-To=3c5f192d0902090436r3e9c905n2edd78019033118%40mail.gmail.com"> + <META NAME="robots" CONTENT="index,nofollow"> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="000066.html"> + <LINK REL="Next" HREF="000072.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[pycrypto] PyCrypto AND Crypt_RSA integration</H1> + <B>Dwayne C. Litzenberger</B> + <A HREF="mailto:pycrypto%40lists.dlitz.net?Subject=%5Bpycrypto%5D%20PyCrypto%20AND%20Crypt_RSA%20integration&In-Reply-To=3c5f192d0902090436r3e9c905n2edd78019033118%40mail.gmail.com" + TITLE="[pycrypto] PyCrypto AND Crypt_RSA integration">dlitz at dlitz.net + </A><BR> + <I>Tue Feb 10 18:32:53 CST 2009</I> + <P><UL> + <LI>Previous message: <A HREF="000066.html">[pycrypto] PyCrypto AND Crypt_RSA integration +</A></li> + <LI>Next message: <A HREF="000072.html">[pycrypto] PyCrypto AND Crypt_RSA integration +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#67">[ date ]</a> + <a href="thread.html#67">[ thread ]</a> + <a href="subject.html#67">[ subject ]</a> + <a href="author.html#67">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>On Mon, Feb 09, 2009 at 10:36:40AM -0200, Mauricio Arozi wrote: +><i>Am I helpless? +</I> +I think the problem is that you're asking the mailing list for the *Python* +Cryptography Toolkit about how to use an obscure *PHP* library. + +We can help with the Python side of things. I wouldn't expect the people +here to know and/or care much about PHP. + +><i> According to this site: <A HREF="http://pajhome.org.uk/crypt/rsa/rsa.html,">http://pajhome.org.uk/crypt/rsa/rsa.html,</A> and +</I>><i> yet others, the e(exponent?) is used for the public key, and d for the +</I>><i> private key. +</I> +The notation I've seen most often is something like this: + + n - modulus (public) + e - public exponent + d - private exponent + (n, e) - public key + (n, d) - private key + (p, q) - the (private) primes from which the keypair is derived. + +PyCrypto uses a similar notation: + + from Crypto.PublicKey import RSA + import os + + # DO NOT USE RandomPool (see below) + keypair = RSA.generate(2048, os.urandom) + + print "PRIVATE KEYPAIR:" + print "n:", keypair.n # modulus (public) + print "e:", keypair.e # public exponent + print "d:", keypair.d # private exponent + print "p:", keypair.p # prime (private) + print "q:", keypair.q # other prime (private) + print "u:", keypair.u # I forget what this for (but it's private) + + pub = keypair.publickey() + print "" + print "PUBLIC KEY:" + print "n (pub):", pub.n # modulus (public) + print "e (pub):", pub.e # public exponent + print "d (pub):", pub.d # raises an exception + print "p (pub):", pub.p # raises an exception + print "q (pub):", pub.q # raises an exception + print "u (pub):", pub.u # raises an exception + +This outputs the following: + + PRIVATE KEYPAIR: + n: 277...[truncated] + e: 65537 + d: 232...[truncated] + p: 159...[truncated] + q: 174...[truncated] + u: 125...[truncated] + + PUBLIC KEY: + n (pub): 277...[truncated] + e (pub): 65537 + d (pub): + Traceback (most recent call last): + File "x.py", line 21, in ? + print "d (pub):", pub.d + File "/usr/lib/python2.4/site-packages/Crypto/PublicKey/RSA.py", line 154, in __getattr__ + return getattr(self.key, attr) + AttributeError: rsaKey instance has no attribute 'd' + +><i> My problem is that while using PyCrypto to generate both public and +</I>><i> private keys, the e(exponent?) is always the same. +</I> +Mads Kiilerich already talked a bit about this, but I won't go into detail. +What you're describing here is normal, and it really helps improve the +performance of encryption/verification. + +If you're concerned about the security of using RSA, I suggest reading Dan +Boneh's 1999 article, "Twenty years of attacks on the RSA cryptosystem": + + <A HREF="http://crypto.stanford.edu/~dabo/abstracts/RSAattack-survey.html">http://crypto.stanford.edu/~dabo/abstracts/RSAattack-survey.html</A> + +><i>So in simple words, I only need to be able to encrypt/decrypt sign and +</I>><i>verify signs on php and python, simultaneously, if possible, using RSA +</I>><i>algo. +</I> +PyCrypto's PublicKey package is very low-level, so people shouldn't use it +directly unless they REALLY know what they are doing. Mere mortals should +use a separate library in addition to PyCrypto for that. You should never +do anything like this: + +><i>privkeyA = RSA.generate(512, rpool.get_bytes) +</I>><i>pubkeyA = privkeyA.publickey() +</I>><i> +</I>><i>msg = 'This is the secret phrase testing.' +</I>><i>msgc = pubkeyA.encrypt(msg, '') +</I> +That is called "textbook RSA", and it's insecure. (Also, it uses a 512-bit +key, which is way too short, but I assume that's just for demonstration.) +I strongly recommend looking at PKCS#1v2 (also known as RSAES-OAEP). +PyCrypto doesn't include an implementation yet, but Sergey Chernov +mentioned that he is working on one. + +Also, I noticed in your code that you used RandomPool. Don't. RandomPool +is a security disaster, and it will be removed from future versions. See +the following messages: + + <A HREF="http://lists.dlitz.net/pipermail/pycrypto/2008q3/000000.html">http://lists.dlitz.net/pipermail/pycrypto/2008q3/000000.html</A> + <A HREF="http://lists.dlitz.net/pipermail/pycrypto/2008q3/000020.html">http://lists.dlitz.net/pipermail/pycrypto/2008q3/000020.html</A> + +I hope you find the above information helpful. + +Cheers, + - Dwayne + +-- +Dwayne C. Litzenberger <<A HREF="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">dlitz at dlitz.net</A>> + Key-signing key - 19E1 1FE8 B3CF F273 ED17 4A24 928C EC13 39C2 5CF7 + Annual key (2008) - 4B2A FD82 FC7D 9E38 38D9 179F 1C11 B877 E780 4B45 +</PRE> + + + + + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="000066.html">[pycrypto] PyCrypto AND Crypt_RSA integration +</A></li> + <LI>Next message: <A HREF="000072.html">[pycrypto] PyCrypto AND Crypt_RSA integration +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#67">[ date ]</a> + <a href="thread.html#67">[ thread ]</a> + <a href="subject.html#67">[ subject ]</a> + <a href="author.html#67">[ author ]</a> + </LI> + </UL> + +<hr> +<a href="http://lists.dlitz.net/cgi-bin/mailman/listinfo/pycrypto">More information about the pycrypto +mailing list</a><br> +</body></html> |