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  • 29 votes cast
Nov
23
awarded  Scholar
Nov
23
accepted For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
Nov
23
comment For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
I'm selecting this as the correct answer, even though @Mikero's answer is also correct, because this one both answers the question I was asking explicitly and the one I was asking implicitly (how to mitigate the dangers of sending an IV plaintext along with a message). That is not to say the other answer is not good (and I've upvoted both), but I think this one is better.
Nov
21
awarded  Editor
Nov
21
revised For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
responded to an answer with a revised proposal
Nov
21
comment For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
So this video seems to say that IV's should be secret as well as random. Is this no longer the case? Or only for protection against esoteric/weak attacks?
Nov
21
comment For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
So that goes against some of the wisdom espoused a few years ago by Bart Preneel in this video, which says that IVs should be kept secret. Note: I don't know how well known or trustworthy he is, but the video was linked to me a while back by someone I trust.
Nov
21
comment For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
Could you pad the first byte with a second random IV, knowing to remove it when decrypting? In this way, you'd be able to protect the IV used throughout while still protecting the first block.
Nov
20
asked For AES CBC, can I encrypt the IV with AES ECB and the same key and include it with the message?
Mar
25
awarded  Student
Mar
13
comment How do I convert the definition of E-521 into a curve definition a la Bouncy Castle?
Thanks for the advice! I'll look into it. It may be in the Java version and not yet in the C# version, so I'll possibly just have some conversion to do.
Mar
12
comment How do I convert the definition of E-521 into a curve definition a la Bouncy Castle?
Ah, I think I have found it. If I'm reading this correctly and assuming that BC implemented the basic Weierstrass-form, then I have to implement the Montgomery form myself or convert it to Weierstrass form. Am I reading this correctly? Are there any performance considerations in this?
Mar
12
comment How do I convert the definition of E-521 into a curve definition a la Bouncy Castle?
That makes sense. Unfortunately, it's what we're relegated to without implementing our own ECC. The FpCurve takes in three BigIntegers, q, a, and b. The question is really, how do I map the definition of the curve to these parameters? I'll look in to the Montgomery though, as it seems (according to SafeCurves) to fit our needs as well.
Mar
12
asked How do I convert the definition of E-521 into a curve definition a la Bouncy Castle?
Jul
27
awarded  Supporter