"Welche Farbe hat der Wind?" - Zen _

.:: A BEAST that decrypts SSL traffic ::.

"Duong and Rizzo say they've figured out a way to defeat SSL by breaking the underlying encryption it uses to prevent sensitive data from being read by people eavesdropping on an address protected by the HTTPs prefix.
Instead, BEAST carries out what's known as a plaintext-recovery attack that exploits a vulnerability in TLS that has long been regarded as mainly a theoretical weakness. During the encryption process, the protocol scrambles block after block of data using the previous encrypted block. It has long been theorized that attackers can manipulate the process to make educated guesses about the contents of the plaintext blocks.

If the attacker's guess is correct, the block cipher will receive the same input for a new block as for an old block, producing an identical ciphertext.

At the moment, BEAST requires about two seconds to decrypt each byte of an encrypted cookie. ”

Quelle: The register
20.09.11 11:50:47 - balle - 651 comments - Kryptografie

.:: Cryptowar 2.0 ::.

"Die amerikanische Regierung will sich per Gesetz die Möglichkeit sichern lassen, auch verschlüsselte Kommunikation mitlesen zu können. Das berichtete die New York Times (NYT) am Montag. Die Regierung von Präsident Barack Obama bricht damit eine Art Stillhalteabkommen und lässt den seit Jahren ruhenden Cryptowar wieder heiß werden.
Explizit gewünscht sind drei Funktionen: Anbieter, die verschlüsselte Kommunikation möglich machen, müssen einen Weg installieren, diese auch zu entschlüsseln; Firmen aus anderen Ländern müssen ein Büro in den USA unterhalten, um Abhöranfragen zu bearbeiten; Entwickler von Peer-to-Peer-Programmen müssen Überwachungsmöglichkeiten einbauen. Wie das technisch umgesetzt wird, bleibt den Anbietern überlassen. So will man verhindern, dass die gesetzlichen Standards in kurzer Zeit technisch überholt sind."

Quelle: Golem

Ähm... Ja nee is klar. Träumt mal weiter, das ist zum Glück technisch nicht machbar ^^
29.09.10 17:23:11 - balle - 882 comments - Kryptografie

.:: DSA VS RSA ::.

Ich hab grad mal zum Thema etwas im Usenet gesucht und folgendes gefunden:

"DSA is the Digital Signature Algorithm, and only does signatures not
encryption. RSA can do both signatures and encryption. It is however
true that DSA keys can be used with some elyptic curve encryption
algorithms to encrypt. Using different keys for encryption and signing
(for certificates and the like) has considerable cryptographic merit,
and while you can use separate keys with RSA, the temptation to use the
same one is frequently overwelming expecially to those who do not
unstand why they should not.

According to Bruce Schneier both DSA and RSA with the same length keys
are just about identical in difficulty to crack. Use the key for
encryption as well as signing and breaking the key gets much easier
simply because there is more data to work with.

SSH uses either DSA or RSA for signing, not encryption, so actually
it makes little difference which you use. As mentioned elsewhere in
this thread US encryption export laws used to mean that DSA was
preferable as it was only for signing and could not be used for
encryption and therefore was allowed to be exported. Following
on from Sept 11 this kind of regulation could come back although
enforcing it would be even harder that it was when implementations
were produced outside the US before the regulations were relaxed.
RSA used to be covered by patent, but that has now lapsed, which
also was a US only problem."

Msg-ID: <afklal$2vo$>
16.02.05 22:10:52 - balle - 1290 comments - Kryptografie

.:: Root Dateisystem verschlüsseln ::.

Da mich jetzt erneut einige Leute gefragt haben wie ich auf meinem Laptop die Root Partition verschlüsselt habe, hier der Link zu dem Howto:
Encrypted Root Filesystem
Swap und /tmp hab ich mit Hilfe der README von Loop AES verschlüsselt.
17.01.05 10:16:53 - balle - 185 comments - Kryptografie

.:: Verschlüsselung für die Mailingliste ::.

10.01.05 07:23:38 - balle - 703 comments - Kryptografie

.:: OpenSSL Zertifikate ::.

How you handle certificates depend a great deal on what your role is.
Your role can be one or several of:

- User of some client software
- User of some server software
- Certificate authority

This file is for users who wish to get a certificate of their own.
05.07.04 20:23:00 - balle - 261 comments - Kryptografie

.:: Dateien verschlüsseln mit OpenSSL ::.

Verschlüsseln (mit AES 256):
openssl enc -e aes256 -in <file_to_encrypt> -out <encrypted_file>

openssl enc -d aes256 -in <ecrypted_file> -out <plain_file>
23.06.04 19:18:35 - balle - 294 comments - Kryptografie

.:: GNUPG Manual ::.

Das Handbuch zur GNU Version von PGP
01.01.04 23:57:00 - balle - 16 comments - Kryptografie

.:: OpenSSL Handbücher ::.

Apache-SSL und OpenSSL Handbücher
01.01.04 23:56:00 - balle - 33 comments - Kryptografie

.:: Crypted filesystems ::.

Wie verschlüsselt man Dateisysteme unter Linux?
01.01.04 23:55:00 - balle - 44 comments - Kryptografie

.:: Tunneling Traffic ::.

Wie tunnelt man Plain Protokolle und schützt sich vor Man-in-the-middle Angriffen?
01.01.04 23:52:00 - balle - 31 comments - Kryptografie

.:: IPsec verstehen und nutzen ::.

Wie funktioniert IPsec und wie bastel ich mir mit FreeS/WAN ein VPN?
01.01.04 23:51:00 - balle - 30 comments - Kryptografie