A real source file shredder?
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Jun Du wrote:
What are reasonable requirements for a source shredder?
IMO, a program which will simply overwrite a file several times with random data, although I read once that it should be several dozen times to be 100% sure it's gone.
See if you can crack this: fb29a481781fe9b3fb8de57cda45fbef
The unofficial awesome history of Code Project's Bob! "People demand freedom of speech to make up for the freedom of thought which they avoid."
If you save a file with random data of the same exact size, I assume it's guarenteed that the same hard drive sectors get overwritten ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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If you save a file with random data of the same exact size, I assume it's guarenteed that the same hard drive sectors get overwritten ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
Yeah, I never understood why it needs to be overwritten that many times unless Schroeder's cat comes into play.
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A recent source file delete program "Secure Delete .Net"[^] reminds me of a real source file shredder. What are reasonable requirements for a source shredder? To me, a couple of requirements are obvious 1) do not delete files but cut them into unrecognised pieces 2) cutting shall be random
Best, Jun
This is somewhat silly. Simply deleting is not enough, as the physical sectors on the disk still hold all data and the file can be reconstructed. Ok, but after overwriting the file once with random data, you can only reconstruct a file by disassembling the disk in a clean room and using special devices to read the magnetic remnants of the overwritten bits. So from there you already are very safe, as someone first has to steal your drive and pay for this not unexpensive procedure. Overwriting the file several times with random data finally also excludes this possibility. I think I could write such a program in a few minutes :)
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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This is somewhat silly. Simply deleting is not enough, as the physical sectors on the disk still hold all data and the file can be reconstructed. Ok, but after overwriting the file once with random data, you can only reconstruct a file by disassembling the disk in a clean room and using special devices to read the magnetic remnants of the overwritten bits. So from there you already are very safe, as someone first has to steal your drive and pay for this not unexpensive procedure. Overwriting the file several times with random data finally also excludes this possibility. I think I could write such a program in a few minutes :)
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
You can overwrite your data as many times as you like. Abby will still be able to read it. ;P
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” I wouldn't let CG touch my Abacus!
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If you save a file with random data of the same exact size, I assume it's guarenteed that the same hard drive sectors get overwritten ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
No, you must open the file while it still exists and write the exact number of bytes it had into it. And you must repeat this procedure several times.
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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You can overwrite your data as many times as you like. Abby will still be able to read it. ;P
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” I wouldn't let CG touch my Abacus!
Sorry for my ignorance. Who's Abby?
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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Jun Du wrote:
What are reasonable requirements for a source shredder?
IMO, a program which will simply overwrite a file several times with random data, although I read once that it should be several dozen times to be 100% sure it's gone.
See if you can crack this: fb29a481781fe9b3fb8de57cda45fbef
The unofficial awesome history of Code Project's Bob! "People demand freedom of speech to make up for the freedom of thought which they avoid."
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Sorry for my ignorance. Who's Abby?
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
Abby[^] is the forensic scientist on the TV show NCIS[^]. As with all of these shows, they manage the impossible with ease.
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” I wouldn't let CG touch my Abacus!
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A recent source file delete program "Secure Delete .Net"[^] reminds me of a real source file shredder. What are reasonable requirements for a source shredder? To me, a couple of requirements are obvious 1) do not delete files but cut them into unrecognised pieces 2) cutting shall be random
Best, Jun
I've heard 6 times is usually the standard, however, I have also heard that the first time you write to the disk (on a new disk), there may be ways to tell which bit was stored. So overwriting may not work on a virgin drive. You may have to prime a drive by filling the disk with random data first. I would know more, but the only computer forensics expert I knew is no longer alive. Sorry I don't have any sources for this, I'll look later.
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Sorry for my ignorance. Who's Abby?
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
The little demon that sits between you and the hard drive. She decides where exactly your bytes go.
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If you save a file with random data of the same exact size, I assume it's guarenteed that the same hard drive sectors get overwritten ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
That is correct. That mean the old file can't be retrieved. Here is am interesting read: Can Intelligence Agencies Read Overwritten Data?[^]
Yusuf May I help you?
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No, you must open the file while it still exists and write the exact number of bytes it had into it. And you must repeat this procedure several times.
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
Yes, that's what I said. Although, as someone else said, if that works, why do you need to do it several times ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
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Abby[^] is the forensic scientist on the TV show NCIS[^]. As with all of these shows, they manage the impossible with ease.
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” I wouldn't let CG touch my Abacus!
Ahh, I have seen that show only a few times. It would have been clear if you had said that Spock could do this with his Tricorder and some logical deduction :)
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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Abby[^] is the forensic scientist on the TV show NCIS[^]. As with all of these shows, they manage the impossible with ease.
Henry Minute Do not read medical books! You could die of a misprint. - Mark Twain Girl: (staring) "Why do you need an icy cucumber?" “I want to report a fraud. The government is lying to us all.” I wouldn't let CG touch my Abacus!
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The little demon that sits between you and the hard drive. She decides where exactly your bytes go.
That demon has many names. Resistance, impedance, inductivity, capacity. It lurks in the wires and solder pads on every printed circuit board. Ever since I soldered together my first computer I have been fighting it and, up to now, always won.
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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Yes, that's what I said. Although, as someone else said, if that works, why do you need to do it several times ?
Christian Graus Driven to the arms of OSX by Vista. Read my blog to find out how I've worked around bugs in Microsoft tools and frameworks.
The magnetic 'shadows' of previous bits written can be measured and analyzed. For this the drive has to be taken apart in a clean room and the disks inside must be analyzed with sensitive equipment. That's quite expensive. Rewriting several times leaves little to be analyzed.
A while ago he asked me what he should have printed on my business cards. I said 'Wizard'. I read books which nobody else understand. Then I do something which nobody understands. After that the computer does something which nobody understands. When asked, I say things about the results which nobody understand. But everybody expects miracles from me on a regular basis. Looks to me like the classical definition of a wizard.
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A recent source file delete program "Secure Delete .Net"[^] reminds me of a real source file shredder. What are reasonable requirements for a source shredder? To me, a couple of requirements are obvious 1) do not delete files but cut them into unrecognised pieces 2) cutting shall be random
Best, Jun
How about an EMP. A big one. Not only will do the file in, but will render the HD unuseable. :)
Chris Meech I am Canadian. [heard in a local bar] In theory there is no difference between theory and practice. In practice there is. [Yogi Berra] posting about Crystal Reports here is like discussing gay marriage on a catholic church’s website.[Nishant Sivakumar]
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I've heard 6 times is usually the standard, however, I have also heard that the first time you write to the disk (on a new disk), there may be ways to tell which bit was stored. So overwriting may not work on a virgin drive. You may have to prime a drive by filling the disk with random data first. I would know more, but the only computer forensics expert I knew is no longer alive. Sorry I don't have any sources for this, I'll look later.
So overwriting may not work on a virgin drive. You may have to prime a drive by filling the disk with random data dinner first.
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So overwriting may not work on a virgin drive. You may have to prime a drive by filling the disk with random data dinner first.
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A recent source file delete program "Secure Delete .Net"[^] reminds me of a real source file shredder. What are reasonable requirements for a source shredder? To me, a couple of requirements are obvious 1) do not delete files but cut them into unrecognised pieces 2) cutting shall be random
Best, Jun
You can always just save it in SourceSafe. That'll shred it. Big time.
I'm not a stalker, I just know things. Oh by the way, you're out of milk.
Forgive your enemies - it messes with their heads