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diff --git a/pipermail/pycrypto/2013q4/000729.html b/pipermail/pycrypto/2013q4/000729.html new file mode 100644 index 0000000..d04a5cc --- /dev/null +++ b/pipermail/pycrypto/2013q4/000729.html @@ -0,0 +1,87 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<HTML> + <HEAD> + <TITLE> [pycrypto] ARC4 examples + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20ARC4%20examples&In-Reply-To=%3CCAGfyce0XedrA%3DpCxWaF9CMA9V_ptzhsP0bXJF6FRg3N_qx7-UQ%40mail.gmail.com%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <style type="text/css"> + pre { + white-space: pre-wrap; /* css-2.1, curent FF, Opera, Safari */ + } + </style> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="000727.html"> + <LINK REL="Next" HREF="000731.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[pycrypto] ARC4 examples</H1> + <B>Legrandin</B> + <A HREF="mailto:pycrypto%40lists.dlitz.net?Subject=Re%3A%20%5Bpycrypto%5D%20ARC4%20examples&In-Reply-To=%3CCAGfyce0XedrA%3DpCxWaF9CMA9V_ptzhsP0bXJF6FRg3N_qx7-UQ%40mail.gmail.com%3E" + TITLE="[pycrypto] ARC4 examples">helderijs at gmail.com + </A><BR> + <I>Wed Nov 20 13:19:33 PST 2013</I> + <P><UL> + <LI>Previous message: <A HREF="000727.html">[pycrypto] ARC4 examples +</A></li> + <LI>Next message: <A HREF="000731.html">[pycrypto] ARC4 examples +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#729">[ date ]</a> + <a href="thread.html#729">[ thread ]</a> + <a href="subject.html#729">[ subject ]</a> + <a href="author.html#729">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>>>>><i> from Crypto.Cipher import ARC4 +</I>>>>><i> from Crypto.Hash import SHA +</I>>>>><i> from Crypto import Random +</I>>>>><i> +</I>>>>><i> key = b'Very long and confidential key' +</I>>>>><i> nonce = Random.new().read(16) +</I>>>>><i> tempkey = SHA.new(key+nonce).digest() +</I>>>>><i> cipher = ARC4.new(tempkey) +</I>>>>><i> msg = nonce + cipher.encrypt(b'Open the pod bay doors, HAL') +</I>><i> +</I>><i> I cannot get that to decrypt to the plaintext. +</I>><i> What is the point of adding the nonce to the ciphertext please, and +</I>><i> how to decrypt? +</I> +It is just one of the many possible ways for delivering the nonce (or +IV) to the receiver. + +If you receive msg, and you have the key, you can decrypt using these steps: + +from Crypto.Cipher import ARC4 +from Crypto.Hash import SHA + +nonce = msg[:16] +tempkey = SHA.new(key+nonce).digest() +cipher = ARC4.new(tempkey) +plaintext = cipher.decrypt(msg[16:]) +</PRE> + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="000727.html">[pycrypto] ARC4 examples +</A></li> + <LI>Next message: <A HREF="000731.html">[pycrypto] ARC4 examples +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#729">[ date ]</a> + <a href="thread.html#729">[ thread ]</a> + <a href="subject.html#729">[ subject ]</a> + <a href="author.html#729">[ 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> |