Linked Questions
11 questions linked to/from Is using a predictable IV with CFB mode safe or not?
13
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2
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Why can't the IV be predictable when its said it doesn't need to be a secret?
I heard multiple times not to reuse the same IV and IV should be random but doesn't need to be secret. I also heard if the IV is something like sequential numbers or something predictable I should ...
user2651
12
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3
answers
3k
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Using a Non-Random IV with modes other than CBC
The weakness CWE-329 is an interesting problem with CBC mode. However, does this same weakness affect the other modes of operation that rely upon an IV such as: PCBC, CFB and OFB? My gut feeling is, ...
- 1,486
3
votes
2
answers
6k
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AES + CBC encryption for a stream of UDP packets
I am developing an application that is based on UDP, and I need to send a stream of packets. As you can imagine, packets can get lost or corrupted. I need to make sure that the content of those ...
- 1,375
9
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2
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467
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Will varying plaintext compensate for a fixed initialisation vector?
This is a follow-up question to Relative merits of AES ECB and CBC modes for securing data at rest.
I need to store encrypted Personal Account Numbers (PANs) in a database. The only encryption option ...
5
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2
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5k
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Encryption for a short packet size
I have an 8051 microcontroller with a radio that can send packets with up to 32 bytes and I want to have the messages encrypted. It is a sensor network so I really only want to send one packet per ...
- 153
4
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4
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Which block cipher modes of operation allow a predictable IV?
Recently I found out that in the modes CBC and PCBC the IV may be passed in cleartext but never must be predictable. However for this part of my app I rather have the IV be predictable and unique (i.e....
user2651
1
vote
1
answer
1k
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Question about IV/initialization vectors
I found some code to get crypto-js to encrypt data in the browser, and with a pointer from someone on SO, it now decodes data as well.
My next question is about the use of an IV; is an IV like a salt ...
- 113
4
votes
1
answer
955
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Fixed-prefix IV in CBC mode
I know the Initialization Vector needs to be unpredictable. Does it apply to the IV as a whole, or to every bit in the IV?
I have multiple devices with poor entropy sharing the same key and I want to ...
- 43
3
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1
answer
946
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Is MCrypt's 8-bit OFB mode secure?
I just stumbled across a Stack Overflow post which points out that the libmcrypt library (notably used in PHP) implements a somewhat unusual set of block cipher modes: it calls the usual CFB and OFB ...
- 45.9k
2
votes
3
answers
382
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Deciphering text encrypted with a changing cipher
I know there are many ways to crack basic ciphers were each letter is mapped to some other letter, but what ways are there to decode something that was encrypted using a cipher that changed after ...
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2
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1
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Is using CFB in SIV secure?
Is SIV mode variant equally secure, if you replace CTR mode encryption with full-block CFB mode encryption?
CFB seems to be safe with predictable IV: Is using a predictable IV with CFB mode safe or ...
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