RE: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-23 Thread John Horton

I do have applied cryptography and only suggested using a larger keysize as
it increases the work factor for a brute force attack. 

-Original Message-
From: Evan Nemerson [mailto:[EMAIL PROTECTED]]
Sent: 22 May 2002 22:39
To: Vinod Panicker; [EMAIL PROTECTED]
Subject: Re: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part
3


Um, it hasn't been proven as the best algorithm. It merely hasn't been 
broken... yet. Actually, many people think IDEA is better. According to
Bruce 
Schneier (creator of blowfish and twofish), "...it is the best and most 
secure block algorithm available to the public at this time..." (Applied 
Cryptography, 2nd Edition, Section 13.9) Twofish, blowfish, AES, 
triple-DES... All are more than enough for pretty much anyone, but none has 
been PROVEN more secure than another, and all will probably be broken 
eventually. Go-go quantum computing ;)

With regards to the "why use AES? Blowfish can have a 448 bit key size!" 
comment, does that mean if I XOR something with a 4096-bit key, I will have 
great security??? Sorry that was approaching flame, but I had to illustrate 
the point- its not just the size of the key that matters; it's how you use 
it! hehe i'm proud of that one.

Now, as for the type of encryption, you really should get a copy of Appled 
Cryptography, 2nd Edition, and read chapter 9. It depends on your 
application. All have pros and cons.



On Wednesday 22 May 2002 02:24 am, Vinod Panicker wrote:
> And why not use AES, which is an industry standard and having
> being proven as the best encryption algorithm in recent times?
>
> http://csrc.nist.gov/encryption/aes/aesfact.html
>
> As far as ECB mode is concerned, I dont know what problems you are
> talking about.  I'm aware that the data gets encrypted in
> independed blocks and its easier to crack it, but its faster than
> other modes.
>
> Tx,
> Vinod.
>
> On Wed, 22 May 2002 John Horton wrote :
> >why use AES? Blowfish can have a 448 bit key size! Also, why use
> >ebc mode
> >with all the problems which come with it?
> >JH
> >
> >-Original Message-
> > From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
> >Sent: 22 May 2002 10:06
> >To: Jimmy Lantz
> >Cc: [EMAIL PROTECTED]
> >Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish?
> >part 3
> >
> >
> >There is no use of hashing in file-encryption except to use it
> >as
> >a check - to see if the decrypted file matches the original
> >file.
> >To do this check, you can use either MD5 or SHA1.  The choice
> >is
> >urs.
> >
> >If ur looking for a good encryption algorithm, you might want
> >to
> >consider AES (Rijndael).  It supports encryption using
> >different
> >key sizes as well as all modes.
> >
> >You can take your pick from ECB / CBC also.  For binary file
> >encryption, i would recommend ECB mode.  For text files, it
> >would
> >be better that you use CBC mode.
> >
> >Tx,
> >Vinod.
> >
> >On Wed, 22 May 2002 Jimmy Lantz wrote :
> > >>I believe that twofish has been successfully broken, so use
> > >>blowfish
> > >>instead. Typically, for encrypting files you will use an
> > >>algorithm like
> > >>blowfish in cbc mode (as opposed to ebc mode) but I don't
> >
> >know
> >
> > >>if Mcrypt
> > >>supports this. Also, when creating the hash of the file, it
> >
> >is
> >
> > >>probably best
> > >>to use SHA-1 instead of MD5, as there appears to be some
> >
> >concern
> >
> > >>with MD5
> > >>over it's compression function.
> > >>HTH
> > >>JH
> > >
> > >It helps :)
> > >I have been looking into Blowfish with cbc mode :)
> > >If I use SHA-1 it's still no way to dehash it during
> >
> >decryption
> >
> > >of the file,
> > >so I fail to see the use of Hashing in fileencryption.
> > >Could someone enlighten me?
> > >/ Jim
> > >
> > >
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> > >To unsubscribe, visit: http://www.php.net/unsub.php
> >
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> >
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Re: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Evan Nemerson

Ah it would be a good idea to use the hash as a checksum- especially if you 
encrypt in ECB


On Wednesday 22 May 2002 01:30 am, Jimmy Lantz wrote:
> >I believe that twofish has been successfully broken, so use blowfish
> >instead. Typically, for encrypting files you will use an algorithm like
> >blowfish in cbc mode (as opposed to ebc mode) but I don't know if Mcrypt
> >supports this. Also, when creating the hash of the file, it is probably
> > best to use SHA-1 instead of MD5, as there appears to be some concern
> > with MD5 over it's compression function.
> >HTH
> >JH
>
> It helps :)
> I have been looking into Blowfish with cbc mode :)
> If I use SHA-1 it's still no way to dehash it during decryption of the
> file, so I fail to see the use of Hashing in fileencryption.
> Could someone enlighten me?
> / Jim


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Re: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Evan Nemerson

Um, it hasn't been proven as the best algorithm. It merely hasn't been 
broken... yet. Actually, many people think IDEA is better. According to Bruce 
Schneier (creator of blowfish and twofish), "...it is the best and most 
secure block algorithm available to the public at this time..." (Applied 
Cryptography, 2nd Edition, Section 13.9) Twofish, blowfish, AES, 
triple-DES... All are more than enough for pretty much anyone, but none has 
been PROVEN more secure than another, and all will probably be broken 
eventually. Go-go quantum computing ;)

With regards to the "why use AES? Blowfish can have a 448 bit key size!" 
comment, does that mean if I XOR something with a 4096-bit key, I will have 
great security??? Sorry that was approaching flame, but I had to illustrate 
the point- its not just the size of the key that matters; it's how you use 
it! hehe i'm proud of that one.

Now, as for the type of encryption, you really should get a copy of Appled 
Cryptography, 2nd Edition, and read chapter 9. It depends on your 
application. All have pros and cons.



On Wednesday 22 May 2002 02:24 am, Vinod Panicker wrote:
> And why not use AES, which is an industry standard and having
> being proven as the best encryption algorithm in recent times?
>
> http://csrc.nist.gov/encryption/aes/aesfact.html
>
> As far as ECB mode is concerned, I dont know what problems you are
> talking about.  I'm aware that the data gets encrypted in
> independed blocks and its easier to crack it, but its faster than
> other modes.
>
> Tx,
> Vinod.
>
> On Wed, 22 May 2002 John Horton wrote :
> >why use AES? Blowfish can have a 448 bit key size! Also, why use
> >ebc mode
> >with all the problems which come with it?
> >JH
> >
> >-Original Message-
> > From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
> >Sent: 22 May 2002 10:06
> >To: Jimmy Lantz
> >Cc: [EMAIL PROTECTED]
> >Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish?
> >part 3
> >
> >
> >There is no use of hashing in file-encryption except to use it
> >as
> >a check - to see if the decrypted file matches the original
> >file.
> >To do this check, you can use either MD5 or SHA1.  The choice
> >is
> >urs.
> >
> >If ur looking for a good encryption algorithm, you might want
> >to
> >consider AES (Rijndael).  It supports encryption using
> >different
> >key sizes as well as all modes.
> >
> >You can take your pick from ECB / CBC also.  For binary file
> >encryption, i would recommend ECB mode.  For text files, it
> >would
> >be better that you use CBC mode.
> >
> >Tx,
> >Vinod.
> >
> >On Wed, 22 May 2002 Jimmy Lantz wrote :
> > >>I believe that twofish has been successfully broken, so use
> > >>blowfish
> > >>instead. Typically, for encrypting files you will use an
> > >>algorithm like
> > >>blowfish in cbc mode (as opposed to ebc mode) but I don't
> >
> >know
> >
> > >>if Mcrypt
> > >>supports this. Also, when creating the hash of the file, it
> >
> >is
> >
> > >>probably best
> > >>to use SHA-1 instead of MD5, as there appears to be some
> >
> >concern
> >
> > >>with MD5
> > >>over it's compression function.
> > >>HTH
> > >>JH
> > >
> > >It helps :)
> > >I have been looking into Blowfish with cbc mode :)
> > >If I use SHA-1 it's still no way to dehash it during
> >
> >decryption
> >
> > >of the file,
> > >so I fail to see the use of Hashing in fileencryption.
> > >Could someone enlighten me?
> > >/ Jim
> > >
> > >
> > >-- PHP General Mailing List (http://www.php.net/)
> > >To unsubscribe, visit: http://www.php.net/unsub.php
> >
> >_
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> >or
> >Abroad
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> >
> >
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>
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Re: RE: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Vinod Panicker

Thats why lots of people like Blowfish, including myself.  I am 
using it in a production environment with PHP and mcrypt.

In ECB mode, the blocks are encrypted independently, whereas in 
CBC mode, the blocks are encrypted with information based on the 
previous block.

What this means is that if a particular block which was encrypted 
using ECB mode is decrypted, it would show the plain text, whereas 
it wont happen if the data was encrypted using CBC mode.

Plain text files can be seen and understood, whereas its much more 
difficult to understand if the crack attempt on a block of binary 
data was successful, since the data wont necessarily make any 
sense.

Tx,
Vinod.

On Wed, 22 May 2002 John Horton wrote :
>One of the reasons I like Blowfish is that I have used it for 
>years, and
>there have been no successfull attempts to crack it.
>Why do you encrypt binary files in ebc and text files in cbc?
>JH
>-Original Message-
> From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
>Sent: 22 May 2002 10:25
>To: John Horton
>Cc: [EMAIL PROTECTED]; Jimmy Lantz
>Subject: Re: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no 
>fish? part
>3
>
>
>And why not use AES, which is an industry standard and having
>being proven as the best encryption algorithm in recent times?
>
>http://csrc.nist.gov/encryption/aes/aesfact.html
>
>As far as ECB mode is concerned, I dont know what problems you 
>are
>talking about.  I'm aware that the data gets encrypted in
>independed blocks and its easier to crack it, but its faster 
>than
>other modes.
>
>Tx,
>Vinod.
>
>On Wed, 22 May 2002 John Horton wrote :
> >why use AES? Blowfish can have a 448 bit key size! Also, why 
>use
> >ebc mode
> >with all the problems which come with it?
> >JH
> >
> >-Original Message-
> > From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
> >Sent: 22 May 2002 10:06
> >To: Jimmy Lantz
> >Cc: [EMAIL PROTECTED]
> >Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no 
>fish?
> >part 3
> >
> >
> >There is no use of hashing in file-encryption except to use 
>it
> >as
> >a check - to see if the decrypted file matches the original
> >file.
> >To do this check, you can use either MD5 or SHA1.  The choice
> >is
> >urs.
> >
> >If ur looking for a good encryption algorithm, you might want
> >to
> >consider AES (Rijndael).  It supports encryption using
> >different
> >key sizes as well as all modes.
> >
> >You can take your pick from ECB / CBC also.  For binary file
> >encryption, i would recommend ECB mode.  For text files, it
> >would
> >be better that you use CBC mode.
> >
> >Tx,
> >Vinod.
> >
> >On Wed, 22 May 2002 Jimmy Lantz wrote :
> > >
> > >
> > >>I believe that twofish has been successfully broken, so 
>use
> > >>blowfish
> > >>instead. Typically, for encrypting files you will use an
> > >>algorithm like
> > >>blowfish in cbc mode (as opposed to ebc mode) but I don't
> >know
> > >>if Mcrypt
> > >>supports this. Also, when creating the hash of the file, 
>it
> >is
> > >>probably best
> > >>to use SHA-1 instead of MD5, as there appears to be some
> >concern
> > >>with MD5
> > >>over it's compression function.
> > >>HTH
> > >>JH
> > >
> > >It helps :)
> > >I have been looking into Blowfish with cbc mode :)
> > >If I use SHA-1 it's still no way to dehash it during
> >decryption
> > >of the file,
> > >so I fail to see the use of Hashing in fileencryption.
> > >Could someone enlighten me?
> > >/ Jim
> > >
> > >
> > >-- PHP General Mailing List (http://www.php.net/)
> > >To unsubscribe, visit: http://www.php.net/unsub.php
> > >
> >
> >_
> >Click below to visit monsterindia.com and review jobs in 
>India
> >or
> >Abroad
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> >
> >
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>
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RE: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread John Horton

One of the reasons I like Blowfish is that I have used it for years, and
there have been no successfull attempts to crack it.
Why do you encrypt binary files in ebc and text files in cbc?
JH
-Original Message-
From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
Sent: 22 May 2002 10:25
To: John Horton
Cc: [EMAIL PROTECTED]; Jimmy Lantz
Subject: Re: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part
3


And why not use AES, which is an industry standard and having 
being proven as the best encryption algorithm in recent times?

http://csrc.nist.gov/encryption/aes/aesfact.html

As far as ECB mode is concerned, I dont know what problems you are 
talking about.  I'm aware that the data gets encrypted in 
independed blocks and its easier to crack it, but its faster than 
other modes.

Tx,
Vinod.

On Wed, 22 May 2002 John Horton wrote :
>why use AES? Blowfish can have a 448 bit key size! Also, why use 
>ebc mode
>with all the problems which come with it?
>JH
>
>-Original Message-
> From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
>Sent: 22 May 2002 10:06
>To: Jimmy Lantz
>Cc: [EMAIL PROTECTED]
>Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? 
>part 3
>
>
>There is no use of hashing in file-encryption except to use it 
>as
>a check - to see if the decrypted file matches the original 
>file.
>To do this check, you can use either MD5 or SHA1.  The choice 
>is
>urs.
>
>If ur looking for a good encryption algorithm, you might want 
>to
>consider AES (Rijndael).  It supports encryption using 
>different
>key sizes as well as all modes.
>
>You can take your pick from ECB / CBC also.  For binary file
>encryption, i would recommend ECB mode.  For text files, it 
>would
>be better that you use CBC mode.
>
>Tx,
>Vinod.
>
>On Wed, 22 May 2002 Jimmy Lantz wrote :
> >
> >
> >>I believe that twofish has been successfully broken, so use
> >>blowfish
> >>instead. Typically, for encrypting files you will use an
> >>algorithm like
> >>blowfish in cbc mode (as opposed to ebc mode) but I don't 
>know
> >>if Mcrypt
> >>supports this. Also, when creating the hash of the file, it 
>is
> >>probably best
> >>to use SHA-1 instead of MD5, as there appears to be some 
>concern
> >>with MD5
> >>over it's compression function.
> >>HTH
> >>JH
> >
> >It helps :)
> >I have been looking into Blowfish with cbc mode :)
> >If I use SHA-1 it's still no way to dehash it during 
>decryption
> >of the file,
> >so I fail to see the use of Hashing in fileencryption.
> >Could someone enlighten me?
> >/ Jim
> >
> >
> >-- PHP General Mailing List (http://www.php.net/)
> >To unsubscribe, visit: http://www.php.net/unsub.php
> >
>
>_
>Click below to visit monsterindia.com and review jobs in India 
>or
>Abroad
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>
>
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Re: RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Vinod Panicker

And why not use AES, which is an industry standard and having 
being proven as the best encryption algorithm in recent times?

http://csrc.nist.gov/encryption/aes/aesfact.html

As far as ECB mode is concerned, I dont know what problems you are 
talking about.  I'm aware that the data gets encrypted in 
independed blocks and its easier to crack it, but its faster than 
other modes.

Tx,
Vinod.

On Wed, 22 May 2002 John Horton wrote :
>why use AES? Blowfish can have a 448 bit key size! Also, why use 
>ebc mode
>with all the problems which come with it?
>JH
>
>-Original Message-
> From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
>Sent: 22 May 2002 10:06
>To: Jimmy Lantz
>Cc: [EMAIL PROTECTED]
>Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? 
>part 3
>
>
>There is no use of hashing in file-encryption except to use it 
>as
>a check - to see if the decrypted file matches the original 
>file.
>To do this check, you can use either MD5 or SHA1.  The choice 
>is
>urs.
>
>If ur looking for a good encryption algorithm, you might want 
>to
>consider AES (Rijndael).  It supports encryption using 
>different
>key sizes as well as all modes.
>
>You can take your pick from ECB / CBC also.  For binary file
>encryption, i would recommend ECB mode.  For text files, it 
>would
>be better that you use CBC mode.
>
>Tx,
>Vinod.
>
>On Wed, 22 May 2002 Jimmy Lantz wrote :
> >
> >
> >>I believe that twofish has been successfully broken, so use
> >>blowfish
> >>instead. Typically, for encrypting files you will use an
> >>algorithm like
> >>blowfish in cbc mode (as opposed to ebc mode) but I don't 
>know
> >>if Mcrypt
> >>supports this. Also, when creating the hash of the file, it 
>is
> >>probably best
> >>to use SHA-1 instead of MD5, as there appears to be some 
>concern
> >>with MD5
> >>over it's compression function.
> >>HTH
> >>JH
> >
> >It helps :)
> >I have been looking into Blowfish with cbc mode :)
> >If I use SHA-1 it's still no way to dehash it during 
>decryption
> >of the file,
> >so I fail to see the use of Hashing in fileencryption.
> >Could someone enlighten me?
> >/ Jim
> >
> >
> >-- PHP General Mailing List (http://www.php.net/)
> >To unsubscribe, visit: http://www.php.net/unsub.php
> >
>
>_
>Click below to visit monsterindia.com and review jobs in India 
>or
>Abroad
>http://monsterindia.rediff.com/jobs
>
>
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RE: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread John Horton

why use AES? Blowfish can have a 448 bit key size! Also, why use ebc mode
with all the problems which come with it?
JH

-Original Message-
From: Vinod Panicker [mailto:[EMAIL PROTECTED]]
Sent: 22 May 2002 10:06
To: Jimmy Lantz
Cc: [EMAIL PROTECTED]
Subject: Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3


There is no use of hashing in file-encryption except to use it as 
a check - to see if the decrypted file matches the original file.  
To do this check, you can use either MD5 or SHA1.  The choice is 
urs.

If ur looking for a good encryption algorithm, you might want to 
consider AES (Rijndael).  It supports encryption using different 
key sizes as well as all modes.

You can take your pick from ECB / CBC also.  For binary file 
encryption, i would recommend ECB mode.  For text files, it would 
be better that you use CBC mode.

Tx,
Vinod.

On Wed, 22 May 2002 Jimmy Lantz wrote :
>
>
>>I believe that twofish has been successfully broken, so use 
>>blowfish
>>instead. Typically, for encrypting files you will use an 
>>algorithm like
>>blowfish in cbc mode (as opposed to ebc mode) but I don't know 
>>if Mcrypt
>>supports this. Also, when creating the hash of the file, it is 
>>probably best
>>to use SHA-1 instead of MD5, as there appears to be some concern 
>>with MD5
>>over it's compression function.
>>HTH
>>JH
>
>It helps :)
>I have been looking into Blowfish with cbc mode :)
>If I use SHA-1 it's still no way to dehash it during decryption 
>of the file,
>so I fail to see the use of Hashing in fileencryption.
>Could someone enlighten me?
>/ Jim
>
>
>-- PHP General Mailing List (http://www.php.net/)
>To unsubscribe, visit: http://www.php.net/unsub.php
>

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RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread John Horton

File hashing is used to take a hash of the clear text. In this way, you can
append the hash to the encrypted text. When decrypting, you remove this
hash, decrypt the rest of the file, hash this decrypted file and see if the
two hashes match up. If they don't then an incorrect key was used with the
algorithm (or the data was corrupted somehow).
Hashes are typically used as sanity checks in this way.
JH

-Original Message-
From: Jimmy Lantz [mailto:[EMAIL PROTECTED]]
Sent: 22 May 2002 09:31
To: [EMAIL PROTECTED]
Subject: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3




>I believe that twofish has been successfully broken, so use blowfish
>instead. Typically, for encrypting files you will use an algorithm like
>blowfish in cbc mode (as opposed to ebc mode) but I don't know if Mcrypt
>supports this. Also, when creating the hash of the file, it is probably
best
>to use SHA-1 instead of MD5, as there appears to be some concern with MD5
>over it's compression function.
>HTH
>JH

It helps :)
I have been looking into Blowfish with cbc mode :)
If I use SHA-1 it's still no way to dehash it during decryption of the file,
so I fail to see the use of Hashing in fileencryption.
Could someone enlighten me?
/ Jim


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Re: RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Vinod Panicker

There is no use of hashing in file-encryption except to use it as 
a check - to see if the decrypted file matches the original file.  
To do this check, you can use either MD5 or SHA1.  The choice is 
urs.

If ur looking for a good encryption algorithm, you might want to 
consider AES (Rijndael).  It supports encryption using different 
key sizes as well as all modes.

You can take your pick from ECB / CBC also.  For binary file 
encryption, i would recommend ECB mode.  For text files, it would 
be better that you use CBC mode.

Tx,
Vinod.

On Wed, 22 May 2002 Jimmy Lantz wrote :
>
>
>>I believe that twofish has been successfully broken, so use 
>>blowfish
>>instead. Typically, for encrypting files you will use an 
>>algorithm like
>>blowfish in cbc mode (as opposed to ebc mode) but I don't know 
>>if Mcrypt
>>supports this. Also, when creating the hash of the file, it is 
>>probably best
>>to use SHA-1 instead of MD5, as there appears to be some concern 
>>with MD5
>>over it's compression function.
>>HTH
>>JH
>
>It helps :)
>I have been looking into Blowfish with cbc mode :)
>If I use SHA-1 it's still no way to dehash it during decryption 
>of the file,
>so I fail to see the use of Hashing in fileencryption.
>Could someone enlighten me?
>/ Jim
>
>
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RE: [PHP] Mcrypt: Blowfish or Twofish or no fish? part 3

2002-05-22 Thread Jimmy Lantz



>I believe that twofish has been successfully broken, so use blowfish
>instead. Typically, for encrypting files you will use an algorithm like
>blowfish in cbc mode (as opposed to ebc mode) but I don't know if Mcrypt
>supports this. Also, when creating the hash of the file, it is probably best
>to use SHA-1 instead of MD5, as there appears to be some concern with MD5
>over it's compression function.
>HTH
>JH

It helps :)
I have been looking into Blowfish with cbc mode :)
If I use SHA-1 it's still no way to dehash it during decryption of the file,
so I fail to see the use of Hashing in fileencryption.
Could someone enlighten me?
/ Jim


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