network profile
| bio | website | |
|---|---|---|
| location | Kiev, Ukraine | |
| age | 22 | |
| visits | member for | 6 months |
| seen | Jan 2 at 7:09 | |
| stats | profile views | 1 |
C++ Programmer in cryptology scope.
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Dec 3 |
comment |
Ensuring integrity of a client side script Do you assume attacker is on channel or a client can be attacker too? In first case you can use something like SSL to protect the channel. |
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Nov 24 |
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Should we sign-then-encrypt, or encrypt-then-sign? @Ricky Demer: signature will be correct only if all decrypted text including padding is identical to the sender's source. So, attacker will take message "Signature is correct" in 2 cases: 1) he pass the message unchanged. 2) He changes ciphertext in some way so the decrypted text is the same as in correct message. The only way to do that is re-encrypting entire message with different IV. I don't think it's possible without knowing the key. |
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Nov 23 |
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Should we sign-then-encrypt, or encrypt-then-sign? Ok, now I finally understood what did you mean. No, recipient is not a padding oracle. he just says "Signature is correct" or "Error". No information of correct or incorrect decryption. Even if attacker can modify ciphertext to be decrypted to the same plaintext, he cannot get any block of this plaintext. |
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Nov 23 |
awarded | Commentator |
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Nov 23 |
comment |
Should we sign-then-encrypt, or encrypt-then-sign? Ok, I'll ask another way: what property of transferred information can be broken? Confidence, integrity, authenticity or what else? |
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Nov 23 |
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Should we sign-then-encrypt, or encrypt-then-sign? So, what is the problem in this case? If recipient get a correct plaintext, no matter how it was derived. |
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Nov 23 |
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Should we sign-then-encrypt, or encrypt-then-sign? If attacker change the ciphertext somehow, the decrypted text will be changed too and signature verification will fail. |
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Nov 23 |
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Should we sign-then-encrypt, or encrypt-then-sign? @Ricky Demer: How can attacker get a plain text? There are no conditions for chosen ciphertext model. |
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Nov 23 |
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detecting ROT13/base64 encryption Both of them are encoding methods. Not an encryption. |
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Nov 23 |
answered | Why shouldn't one build a MAC by XORing multiple message blocks? |
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Nov 23 |
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Encrypting with private key in Public Key InfraStructure You are doing it wrong. Encryption of hash with RSA private key is called signing. Note, that RSA is one of the few ciphers that provide signature as encryption with private key. The goal of second operation is not clear. Why you encrypt a symmetric key? I see you need classic sign-then-encrypt scheme. |
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Nov 23 |
answered | Should we sign-then-encrypt, or encrypt-then-sign? |
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Nov 19 |
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Is there an authenticated encryption scheme where the recipient can attribute the message to a single sender? That's not the same. MAC is based on secret key and cannot compromise sigher's identity. |
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Nov 19 |
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Is this how padding can work? Padding is applied to plaintext, not ciphertext. |
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Nov 19 |
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Is it safer to encrypt twice with RSA? It will be impossible with padding due to encrypted message size. |
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Nov 19 |
awarded | Teacher |
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Nov 19 |
answered | Is it safer to encrypt twice with RSA? |
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Nov 19 |
comment |
Is this how padding can work? So, what is the problem? Last byte will contain the block length, so you will know that entire last block is a padding. |
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Nov 19 |
answered | Is there an authenticated encryption scheme where the recipient can attribute the message to a single sender? |
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Nov 19 |
awarded | Supporter |
