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visits member for 1 year, 6 months
seen Oct 17 at 1:35

Semi-competent user and consciously incompetent implementer of cryptography. Math hurts my head.


Oct
17
reviewed Close Side channel vulnerabilities in SW RSA implementations?
Oct
17
reviewed Close How would I write my own asymmetric encryption algorithm (not RSA, DES etc)?
Oct
17
reviewed Close How do you test randomness?
Oct
17
reviewed No Action Needed Encrypting twice with different modes?
Oct
17
reviewed No Action Needed Prove that the affine cipher over Z26 has perfect secrecy if every key is used with equal probability of 1/312
Oct
17
reviewed Looks OK I need to know number of encryption/decryption operations?
Oct
17
reviewed Leave Closed ECC encryption with Miracle Library in C
Oct
17
answered blowfish ecb with openssl doesn't give the expected result
Oct
14
reviewed Leave Open RSA given q, p and e?
Oct
14
reviewed Close How to use the key from a Diffie Hellman exchange?
Oct
14
reviewed Close Weak key schedule IDEA
Oct
14
reviewed Leave Open how does the order-preserving encryption scheme distribute the buckets?
Sep
30
awarded  Explainer
Sep
24
awarded  Autobiographer
Aug
28
reviewed Close How does Random Oracle and Standard Model differ?
Aug
28
comment Choice of authenticated encryption mode for whole messages
@e-sushi "And in case of doubt, have a look at the OCB-AES128, OCB-AES192, and OCB-AES256 test vectors" - last I looked those were all 128 bit block size ;). I was referencing RFC 7253 which explicitly limits the standardised OCB to 128 bits, but I take your point that OCB in general can use different block sizes. My question about the critique of CCM stands though...
Aug
28
comment Choice of authenticated encryption mode for whole messages
"Also, GCM has a pretty good performance" - this should really be can have pretty good performance. As @SquareRootOfTwentyThree's answer notes, non hardware/SIMD-accelerated table based GCM (e.g. pure Java impls) is either memory intensive (typically 8k of key dependant tables for decent speed) or unbearably slow. On many platforms, GCM can be unusable, while CCM/EAX will still perform reasonably.
Aug
28
comment Choice of authenticated encryption mode for whole messages
"... CCM. That mode is only defined for block ciphers with a block length of 128 bits" - I don't understand this as a critique of CCM, since this statement is true of GCM and OCB as well (EAX can be used with arbitrary block sizes). The major critiques of CCM are usually speed (2-pass) and that it's packet mode.
Aug
16
reviewed Leave Open Implementation Attacks on Hashes
Aug
16
reviewed No Action Needed Using hashes as passwords