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Is it possible to determine the symmetric encryption method used by output size?
Symmetric encryption mode where ciphertext size is plain text sizeUsing IV buffer after altered inside a Rijndael CBC Encryption/Decryption process as IV for next message?Exercise: Attack on a Two-Round DES CipherCommon password derivation function for different encryption methodsCracking an appliance's network protocolDetermine encryption method with input and outputSymmetric encryption vulnerable when encrypting and decrypting are the same?Is this an acceptable way to increase the block size of a block cipher?Crypto algorithm identification (reverse engineering)In BBC Sherlock's The Blind Banker, what type of cryptographic function is used by the Black Lotus?
$begingroup$
I'm attempting to identify the method of encryption for a black-box symmetric encryptor that produces blocks of output that are 4 bytes in length (e.g. small inputs fit in 16 bytes, then 20 bytes and 24 bytes as more input characters are added).
It's symmetric encryption and the value is always the same for the same input text. Is it possible to determine which method of encryption is used? I'm assuming it's a block cipher as a result of the blocks of output it produces.
block-cipher symmetric blocksize
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
add a comment |
$begingroup$
I'm attempting to identify the method of encryption for a black-box symmetric encryptor that produces blocks of output that are 4 bytes in length (e.g. small inputs fit in 16 bytes, then 20 bytes and 24 bytes as more input characters are added).
It's symmetric encryption and the value is always the same for the same input text. Is it possible to determine which method of encryption is used? I'm assuming it's a block cipher as a result of the blocks of output it produces.
block-cipher symmetric blocksize
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago
add a comment |
$begingroup$
I'm attempting to identify the method of encryption for a black-box symmetric encryptor that produces blocks of output that are 4 bytes in length (e.g. small inputs fit in 16 bytes, then 20 bytes and 24 bytes as more input characters are added).
It's symmetric encryption and the value is always the same for the same input text. Is it possible to determine which method of encryption is used? I'm assuming it's a block cipher as a result of the blocks of output it produces.
block-cipher symmetric blocksize
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$endgroup$
I'm attempting to identify the method of encryption for a black-box symmetric encryptor that produces blocks of output that are 4 bytes in length (e.g. small inputs fit in 16 bytes, then 20 bytes and 24 bytes as more input characters are added).
It's symmetric encryption and the value is always the same for the same input text. Is it possible to determine which method of encryption is used? I'm assuming it's a block cipher as a result of the blocks of output it produces.
block-cipher symmetric blocksize
block-cipher symmetric blocksize
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
edited 3 hours ago
jSherz
asked 3 hours ago
jSherzjSherz
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
asked 3 hours ago
jSherzjSherz
1064
asked 3 hours ago
jSherzjSherz
1064
1064
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
New contributor
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
jSherz is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago
add a comment |
$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago
$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago
$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago
add a comment |
1 Answer
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$begingroup$
Simply put: No.
Without knowing other details, you cannot be sure. That being said, in the case you described, the black box uses 4 bytes blocks, which is rather uncommon with modern block ciphers. AES e.g. uses 128bits (16bytes), Blowfish uses 64bits (8bytes). 4byte block ciphers are very uncommon now. Even DES, which is quite outdated and old uses 8 bytes. The only block cipher used that has 32bit block size and comes to my mind is RC5.
So as you can see, you can make an educated guess. But given just the ciphertext, this does not inform you at all about encryption used. This is one of the key aspects of cryptography btw, encrypted data should look as much as random data as possible.
You cannot even be sure that this is a block cipher. Could be a stream cipher with padding. So if the only thing you know is: "I have a box. I feed it data and it spits out data in chunks of 4 bytes" - then you know nothin', j Sherz
answered 2 hours ago
michnovkamichnovka
19229
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$begingroup$
Simply put: No.
Without knowing other details, you cannot be sure. That being said, in the case you described, the black box uses 4 bytes blocks, which is rather uncommon with modern block ciphers. AES e.g. uses 128bits (16bytes), Blowfish uses 64bits (8bytes). 4byte block ciphers are very uncommon now. Even DES, which is quite outdated and old uses 8 bytes. The only block cipher used that has 32bit block size and comes to my mind is RC5.
So as you can see, you can make an educated guess. But given just the ciphertext, this does not inform you at all about encryption used. This is one of the key aspects of cryptography btw, encrypted data should look as much as random data as possible.
You cannot even be sure that this is a block cipher. Could be a stream cipher with padding. So if the only thing you know is: "I have a box. I feed it data and it spits out data in chunks of 4 bytes" - then you know nothin', j Sherz
answered 2 hours ago
michnovkamichnovka
19229
$endgroup$
add a comment |
$begingroup$
Simply put: No.
Without knowing other details, you cannot be sure. That being said, in the case you described, the black box uses 4 bytes blocks, which is rather uncommon with modern block ciphers. AES e.g. uses 128bits (16bytes), Blowfish uses 64bits (8bytes). 4byte block ciphers are very uncommon now. Even DES, which is quite outdated and old uses 8 bytes. The only block cipher used that has 32bit block size and comes to my mind is RC5.
So as you can see, you can make an educated guess. But given just the ciphertext, this does not inform you at all about encryption used. This is one of the key aspects of cryptography btw, encrypted data should look as much as random data as possible.
You cannot even be sure that this is a block cipher. Could be a stream cipher with padding. So if the only thing you know is: "I have a box. I feed it data and it spits out data in chunks of 4 bytes" - then you know nothin', j Sherz
answered 2 hours ago
michnovkamichnovka
19229
$endgroup$
add a comment |
$begingroup$
Simply put: No.
Without knowing other details, you cannot be sure. That being said, in the case you described, the black box uses 4 bytes blocks, which is rather uncommon with modern block ciphers. AES e.g. uses 128bits (16bytes), Blowfish uses 64bits (8bytes). 4byte block ciphers are very uncommon now. Even DES, which is quite outdated and old uses 8 bytes. The only block cipher used that has 32bit block size and comes to my mind is RC5.
So as you can see, you can make an educated guess. But given just the ciphertext, this does not inform you at all about encryption used. This is one of the key aspects of cryptography btw, encrypted data should look as much as random data as possible.
You cannot even be sure that this is a block cipher. Could be a stream cipher with padding. So if the only thing you know is: "I have a box. I feed it data and it spits out data in chunks of 4 bytes" - then you know nothin', j Sherz
answered 2 hours ago
michnovkamichnovka
19229
$endgroup$
Simply put: No.
Without knowing other details, you cannot be sure. That being said, in the case you described, the black box uses 4 bytes blocks, which is rather uncommon with modern block ciphers. AES e.g. uses 128bits (16bytes), Blowfish uses 64bits (8bytes). 4byte block ciphers are very uncommon now. Even DES, which is quite outdated and old uses 8 bytes. The only block cipher used that has 32bit block size and comes to my mind is RC5.
So as you can see, you can make an educated guess. But given just the ciphertext, this does not inform you at all about encryption used. This is one of the key aspects of cryptography btw, encrypted data should look as much as random data as possible.
You cannot even be sure that this is a block cipher. Could be a stream cipher with padding. So if the only thing you know is: "I have a box. I feed it data and it spits out data in chunks of 4 bytes" - then you know nothin', j Sherz
answered 2 hours ago
michnovkamichnovka
19229
edited 2 hours ago
answered 2 hours ago
michnovkamichnovka
19229
answered 2 hours ago
michnovkamichnovka
19229
answered 2 hours ago
michnovkamichnovka
19229
19229
add a comment |
add a comment |
jSherz is a new contributor. Be nice, and check out our Code of Conduct.
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$begingroup$
Related question on security.SE: security.stackexchange.com/questions/38797/… (I thought I remembered seeing a duplicate or at least a very similar question before on this site as well, but if so, I can't find it.)
$endgroup$
– Ilmari Karonen
2 hours ago