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bio website github.com/CodesInChaos
location Frankfurt, Germany
age
visits member for 3 years
seen 13 mins ago

Oct
24
comment RSA decrypt long messages (javascript)
Your formatting problem was that you attempted to use LaTeX ($$) formatting instead of code formatting (indent by four spaces).
Oct
24
revised RSA decrypt long messages (javascript)
added 55 characters in body
Oct
23
comment Is there a “brainwallet” for GPG keys?
@ralu The coding part is easy. Typical password quality is a problem, especially since you can't use salts.
Oct
23
comment Having 4096 bit keys and short (< 256 byte) messages, can I simply use the key as OTP?
1) You still need a MAC, luckily for you polynomial MACs are provably secure (with a certain probability of not detecting the error which is independent of attackers computation resources) 2) The problem with OTP is exchanging those keys and that you need state to ensure that you never reuse a key.
Oct
23
comment Is there a “brainwallet” for GPG keys?
Same problem as for all password based encryption, except a bit worse since it's not possible to use salts. So whenever practical, encrypt your private key with the password instead of using a password as seed.
Oct
23
comment Open source implementations of Symmetric Searchable Encryption and Order Preserving Encryption
1) These kinds of encryption are inherently weak 2) Take a look at CryptDB
Oct
23
answered Can I use the ChaCha core as a 256-bit to 256-bit one-way function?
Oct
23
comment Can I use the ChaCha core as a 256-bit to 256-bit one-way function?
@nightcracker For the one-way function part, yes. But you'll also need a collision resistant hash for the message.
Oct
23
comment Can I safely replace XOR with ADD in a stream cipher?
@HannoBinder If your stream cipher is so broken that this makes a difference, run.
Oct
23
comment Can I use the ChaCha core as a 256-bit to 256-bit one-way function?
@RickyDemer I don't know much about that, but DJB emphasized that Salsa20 is designed as a cipher, not as a collision resistant hash. He even renamed the core from "hash" to "core" to avoid misunderstandings. "The Salsa20 core does not compress and is not collision-resistant."
Oct
23
reviewed Approve suggested edit on salsa20 tag wiki excerpt
Oct
23
reviewed Approve suggested edit on salsa20 tag wiki
Oct
23
comment In RSA, what is faster attacking “d” when plaintext is known, or factoring when M is unknown?
1) Any native brute-force is ridiculously more expensive than sieving based attack. You can't even brute-force RSA-256 2) Why do you say "no plaintext available"? Since RSA is asymmetric, an attacker can produce as many plaintext/ciphertext pair as they like.
Oct
23
comment Can I use the ChaCha core as a 256-bit to 256-bit one-way function?
If you only need one-way-ness / first pre-image resistance, you should be fine, since that maps directly to a key recovery attack on ChaCha. If you need collision resistance, don't use it.
Oct
23
comment MARS and RC6 in CUDA
As a side-note: You should target ATI CPUs as well, those usually have higher performance for crypto.
Oct
22
comment What block cipher is used for CBC-MAC?
CBC-MAC is fine with variable length messages, as long as you never have one message that's a prefix of another. For example a length prefix can achieve that if you know the length of the message beforehand.
Oct
22
comment Should I trust CipherCloud?
Looks like they came up with a major cryptography break-through this month: You can use AES with a random IV. True pioneers who boldly go where no man has gone before.
Oct
22
revised Genuine encryption from only one source?
edited title
Oct
22
reviewed Approve suggested edit on What block cipher is used for CBC-MAC?
Oct
21
comment Genuine encryption from only one source?
Does a standard digital signature fit your scenario?