(Successful) Dictionary Attack Against Private Keys

[johnyj]

What happens if you find a key with 1000 BTC and can't determine the owner? 

Remove 1 bitcoin from that address to infom the owner that the key is compromised 

[1714899339]

1714899339

[1714899339]

1714899339

[1714899339]

1714899339

[gmaxwell]

Ask the user for their full name, DOB, and/or any other personal information. 

So I did a little informal study of this on IRC with a little test page, and it was basically impossible convince people that their personal information wasn't being "connected" to their account in some way.  (and to some extent it is: someone who had their credentials recovered would have a harder time denying them).   This is least recovers from the saltlessness problem, though it leaves the door open for targeted attacks against passwords which are almost never strong enough... but I can't figure out how to get the user past the "personal information" problem.

[cryptocoinsnews]

http://www.cryptocoinsnews.com/2013/09/05/dictionary-attack-against-private-bitcoin-keys/

[Sothh]

correct horse battery staple

has thousands of transactions and has all this dust in it.  People are making transfers in and out.  Are they collecting the dust?  If I import the key into Armory wallet it crashes it when it tries to look at the transactions.

Ninja post.  https://bitcointalk.org/index.php?topic=288295.msg3087310#new

[Sothh]

correct horse battery staple

has thousands of transactions and has all this dust in it.  People are making transfers in and out.  Are they collecting the dust?  If I import the key into Armory wallet it crashes it when it tries to look at the transactions.

Ninja post.  https://bitcointalk.org/index.php?topic=288295.msg3087310#new

Ha, less than 2 minutes difference.  It is because someone mentioned it on reddit.

I actually found it myself last night, but did not have time to post about it.

[champbronc2]

It's not a glitch lol

[LAMarcellus]

Ok. I sent chocolate and Basketball. Give some more.

Please don't crap up the utxo set keeping around more of these junk outputs.

When you redeem these things, send them to an OP_RETURN txout with a value of 0.  This will convert the output into fees and prevent a new output from being created in the txout set.

Is there a tut or guide where I can learn more about command like OP_RETURN txout?


Also for what its worth,
These topics need to be brought up and refreshed opn occassion for the benefit of new users and continuing ed for old users alike.

[fat%]

Alright, so it looks like I managed to find the private keys of at least 13 addresses with positive balances (always 0.0000546) over the last 20 minutes or so. What I did was I visited http://en.wikipedia.org/wiki/List_of_Latin_words_with_English_derivatives and manually picked some random words from that list, entered them as a passphrase at brainwallet.com and manually looked up if the addresses were used before. Until now I found the following private keys with corresponding addresses:

TERM	PRIVATE KEY	ADDRESS	LINK
important	5JDUmWkA82w4Pas8j4eARzQeZtdReUoishzoBEgRGSFMcj2YBos	1GzbteqnMuDRU4iYeqka5YkgbhcA3qxTJd	Here
different	5K1d51cwAVq83qkBVzhHZ8u5xtSauctmCtJPf6g7BdDWaykHRFF	13zJp8PV7cY2cgLubFQzDFihHArgBgtM3C	Here
government	5K7kzFpqBTiegqevfc61pyCkzb6ds6hfvHP1rEWXqR7SXC3MMkj	1PXegNYkYCvkYsrDb3kxoQRQNh9VWToJBm	Here
insurance	5Jaj9sMkoLYzwtcv7UUjF69VUwyov5iTtXHQE6f2Mc8Ca5MkBrE	19RFdcSUJtFRusvc2uKTUnmx9PcR1tXgca	Here
medicines	5KZPBNWe2Fp7MZevX7JdghoZnXuXG7R27TThCKxj9kve2Nf4V7z	1Am8qpytgq1ySjesufAcdZw1buDnfKg3B8	Here
materials	5K9gHpgLZmVjejRDveJPEhCk8n33NdxPfr5tQzYDNdrkpPKB8bm	16zBDyZfRz2DbHSw5YXFUCaFJK48UkphpD	Here
perceived	5KjV1dJE58aFPB5HvTs8nbuQe8r8fUvHFEh3Pu8hQ8A7qSChEsi	1Ajzkqundi3i8SAZEUifXJcy79egAGCh7P	Here
patriotic	5JoQrSF3Bmi2NwZtspvqrXB1Am5SjnPUTYABT5r5gTi66ZHUiuV	16Urcu2LRTbZvGU5hujENx4MfjEMTfrosi	Here
amplitude	5JRUt4fu5n9c9mLTBGPv93jan16pxZhvwA23dUCwE5wtYr6jQbP	14Smg3UD6DaQhveJp17WuX4N2pffR4QiGC	Here
anniversary	5JJoefcjSo9SKn2eZE6VndoeaPC1PY9wMp6NHPzLCDjp2hqyqPM	14wMQhfw4bFFxzcyUVzgmVamjCjzXeozuJ	Here
amplification	5KNUAQKqdeHASbXrJSXs894RMk8K9QPE7DBPtyL42yVGLpTR5Wy	15f9gbgshS1LM7tYaEJYHZ3EQJU9dL2NRU	Here
triangular	5KR8CRg662edTqU4AmPKEAVbg8Qj9RA1WbY6MNzb64T4kAyzDLV	1P8JccH4BnQ5snwE6Mj6C9pu4hAUbfbhhi	Here
abbreviation	5JR7aQHZuYisNYHUTXnVML66Vy731EYW5B3W6ztJTthJun35iUa	1H9pZi9gypLwz2kRqn9kMnKfFopFY14EyN	Here

Note: The address sending the BTC to the minor ones is always this one: 1HoVUP4cSjsUQXR2dSMN8wXTLct2EbiSAB with the same transaction ID 632856fb634e50f0bba8ebe0b20798256c70a6626bcbf3d1cb4e16590a79da9f. There was only one major transaction of 0.0463834 BTC from the same address to this one 1J8GRz2nMmGYP6XQSfUnBgGzw9s6HSZEZU. The 500 minor ones add up to a total of 0.0358 BTC. Due to the fact that manually guessing the private keys of all 500 addresses is very time consuming and does not yield a high amount of BTC I don't think I'll continue doing so. Importing the 13 addresses into my wallet took me roughly 7-8 minutes per address, adding up to a total of about somewhat less than 2 hours after having found the private keys.

Conclusion: Whoever did this: You've been busted. Better not use the "List of Latin words with English derivatives" as the basis of your brainwallet based addresses. There are also some other lists I have not tried out yet, but you are free to do so.

Jeez, tossing is hard, but fun.

[virtualmaster]

Alright, so it looks like I managed to find the private keys of at least 13 addresses with positive balances (always 0.0000546) over the last 20 minutes or so. What I did was I visited http://en.wikipedia.org/wiki/List_of_Latin_words_with_English_derivatives and manually picked some random words from that list, entered them as a passphrase at brainwallet.com and manually looked up if the addresses were used before. Until now I found the following private keys with corresponding addresses:

TERM	PRIVATE KEY	ADDRESS	LINK
important	5JDUmWkA82w4Pas8j4eARzQeZtdReUoishzoBEgRGSFMcj2YBos	1GzbteqnMuDRU4iYeqka5YkgbhcA3qxTJd	Here
different	5K1d51cwAVq83qkBVzhHZ8u5xtSauctmCtJPf6g7BdDWaykHRFF	13zJp8PV7cY2cgLubFQzDFihHArgBgtM3C	Here
government	5K7kzFpqBTiegqevfc61pyCkzb6ds6hfvHP1rEWXqR7SXC3MMkj	1PXegNYkYCvkYsrDb3kxoQRQNh9VWToJBm	Here
insurance	5Jaj9sMkoLYzwtcv7UUjF69VUwyov5iTtXHQE6f2Mc8Ca5MkBrE	19RFdcSUJtFRusvc2uKTUnmx9PcR1tXgca	Here
medicines	5KZPBNWe2Fp7MZevX7JdghoZnXuXG7R27TThCKxj9kve2Nf4V7z	1Am8qpytgq1ySjesufAcdZw1buDnfKg3B8	Here
materials	5K9gHpgLZmVjejRDveJPEhCk8n33NdxPfr5tQzYDNdrkpPKB8bm	16zBDyZfRz2DbHSw5YXFUCaFJK48UkphpD	Here
perceived	5KjV1dJE58aFPB5HvTs8nbuQe8r8fUvHFEh3Pu8hQ8A7qSChEsi	1Ajzkqundi3i8SAZEUifXJcy79egAGCh7P	Here
patriotic	5JoQrSF3Bmi2NwZtspvqrXB1Am5SjnPUTYABT5r5gTi66ZHUiuV	16Urcu2LRTbZvGU5hujENx4MfjEMTfrosi	Here
amplitude	5JRUt4fu5n9c9mLTBGPv93jan16pxZhvwA23dUCwE5wtYr6jQbP	14Smg3UD6DaQhveJp17WuX4N2pffR4QiGC	Here
anniversary	5JJoefcjSo9SKn2eZE6VndoeaPC1PY9wMp6NHPzLCDjp2hqyqPM	14wMQhfw4bFFxzcyUVzgmVamjCjzXeozuJ	Here
amplification	5KNUAQKqdeHASbXrJSXs894RMk8K9QPE7DBPtyL42yVGLpTR5Wy	15f9gbgshS1LM7tYaEJYHZ3EQJU9dL2NRU	Here
triangular	5KR8CRg662edTqU4AmPKEAVbg8Qj9RA1WbY6MNzb64T4kAyzDLV	1P8JccH4BnQ5snwE6Mj6C9pu4hAUbfbhhi	Here
abbreviation	5JR7aQHZuYisNYHUTXnVML66Vy731EYW5B3W6ztJTthJun35iUa	1H9pZi9gypLwz2kRqn9kMnKfFopFY14EyN	Here

Note: The address sending the BTC to the minor ones is always this one: 1HoVUP4cSjsUQXR2dSMN8wXTLct2EbiSAB with the same transaction ID 632856fb634e50f0bba8ebe0b20798256c70a6626bcbf3d1cb4e16590a79da9f. There was only one major transaction of 0.0463834 BTC from the same address to this one 1J8GRz2nMmGYP6XQSfUnBgGzw9s6HSZEZU. The 500 minor ones add up to a total of 0.0358 BTC. Due to the fact that manually guessing the private keys of all 500 addresses is very time consuming and does not yield a high amount of BTC I don't think I'll continue doing so. Importing the 13 addresses into my wallet took me roughly 7-8 minutes per address, adding up to a total of about somewhat less that 2 hours after having found the private keys.

Conclusion: Whoever did this: You've been busted. Better not use the "List of Latin words with English derivatives" as the basis of your brainwallet based addresses. There are also some other lists I have not tried out yet, but you are free to do so.

Jeez, tossing is hard, but fun.

It is highly improbably to be a successful dictionary attack by amounts less of 1 mBTC. It is more probable that it was a test or a communication.

[fat%]

Alright, so it looks like I managed to find the private keys of at least 13 addresses with positive balances (always 0.0000546) over the last 20 minutes or so. What I did was I visited http://en.wikipedia.org/wiki/List_of_Latin_words_with_English_derivatives and manually picked some random words from that list, entered them as a passphrase at brainwallet.com and manually looked up if the addresses were used before. Until now I found the following private keys with corresponding addresses:

TERM	PRIVATE KEY	ADDRESS	LINK
important	5JDUmWkA82w4Pas8j4eARzQeZtdReUoishzoBEgRGSFMcj2YBos	1GzbteqnMuDRU4iYeqka5YkgbhcA3qxTJd	Here
different	5K1d51cwAVq83qkBVzhHZ8u5xtSauctmCtJPf6g7BdDWaykHRFF	13zJp8PV7cY2cgLubFQzDFihHArgBgtM3C	Here
government	5K7kzFpqBTiegqevfc61pyCkzb6ds6hfvHP1rEWXqR7SXC3MMkj	1PXegNYkYCvkYsrDb3kxoQRQNh9VWToJBm	Here
insurance	5Jaj9sMkoLYzwtcv7UUjF69VUwyov5iTtXHQE6f2Mc8Ca5MkBrE	19RFdcSUJtFRusvc2uKTUnmx9PcR1tXgca	Here
medicines	5KZPBNWe2Fp7MZevX7JdghoZnXuXG7R27TThCKxj9kve2Nf4V7z	1Am8qpytgq1ySjesufAcdZw1buDnfKg3B8	Here
materials	5K9gHpgLZmVjejRDveJPEhCk8n33NdxPfr5tQzYDNdrkpPKB8bm	16zBDyZfRz2DbHSw5YXFUCaFJK48UkphpD	Here
perceived	5KjV1dJE58aFPB5HvTs8nbuQe8r8fUvHFEh3Pu8hQ8A7qSChEsi	1Ajzkqundi3i8SAZEUifXJcy79egAGCh7P	Here
patriotic	5JoQrSF3Bmi2NwZtspvqrXB1Am5SjnPUTYABT5r5gTi66ZHUiuV	16Urcu2LRTbZvGU5hujENx4MfjEMTfrosi	Here
amplitude	5JRUt4fu5n9c9mLTBGPv93jan16pxZhvwA23dUCwE5wtYr6jQbP	14Smg3UD6DaQhveJp17WuX4N2pffR4QiGC	Here
anniversary	5JJoefcjSo9SKn2eZE6VndoeaPC1PY9wMp6NHPzLCDjp2hqyqPM	14wMQhfw4bFFxzcyUVzgmVamjCjzXeozuJ	Here
amplification	5KNUAQKqdeHASbXrJSXs894RMk8K9QPE7DBPtyL42yVGLpTR5Wy	15f9gbgshS1LM7tYaEJYHZ3EQJU9dL2NRU	Here
triangular	5KR8CRg662edTqU4AmPKEAVbg8Qj9RA1WbY6MNzb64T4kAyzDLV	1P8JccH4BnQ5snwE6Mj6C9pu4hAUbfbhhi	Here
abbreviation	5JR7aQHZuYisNYHUTXnVML66Vy731EYW5B3W6ztJTthJun35iUa	1H9pZi9gypLwz2kRqn9kMnKfFopFY14EyN	Here

Note: The address sending the BTC to the minor ones is always this one: 1HoVUP4cSjsUQXR2dSMN8wXTLct2EbiSAB with the same transaction ID 632856fb634e50f0bba8ebe0b20798256c70a6626bcbf3d1cb4e16590a79da9f. There was only one major transaction of 0.0463834 BTC from the same address to this one 1J8GRz2nMmGYP6XQSfUnBgGzw9s6HSZEZU. The 500 minor ones add up to a total of 0.0358 BTC. Due to the fact that manually guessing the private keys of all 500 addresses is very time consuming and does not yield a high amount of BTC I don't think I'll continue doing so. Importing the 13 addresses into my wallet took me roughly 7-8 minutes per address, adding up to a total of about somewhat less that 2 hours after having found the private keys.

Conclusion: Whoever did this: You've been busted. Better not use the "List of Latin words with English derivatives" as the basis of your brainwallet based addresses. There are also some other lists I have not tried out yet, but you are free to do so.

Jeez, tossing is hard, but fun.

It is highly improbably to be a successful dictionary attack by amounts less of 1 mBTC. It is more probable that it was a test or a communication.

Well, might be true. But it worked out. Tried "investigation" and "ambulance", same result. All latin based derivatives.

[gmaxwell]

To get rid of these junk "password testing outputs" don't create yet more outputs, here is how you make a transaction to defragment the utxo set:

For this game we'll need a copy of bitcoind or the bitcoinqt debug console. You don't need a synced up blockchain, unless you're going to use it to look up the scriptPubKeys, and if you are you'll need the node to be running with txindex=1 in the configuration.  You'll also want this patch so that you can relay OP_RETURN transactions, and a configuration which addnode=173.242.112.53  and addnode=relay.eligius.st  to make sure the OP_RETURN transactions get relayed to someone who will mine them.

First figure out the txid:vouts  you'll be spending.

Then run

$ bitcoind createrawtransaction '[{"txid":"50bb362e201ed2246a415dad53f63cbb41b88c145ea7a41ee111b9e4353f80f5","vout":224},{"txid":"dda2e022a81ac6dcc219bd1a8bc7038bf55f5039b8a74a78ac473b6b32a5d146","vout":414}]' '{"1GMaxweLLbo8mdXvnnC19Wt2wigiYUKgEB":1e-8}'


The destination doesn't matter as you'll see in a moment.

This will return:
0100000002f5803f35e4b911e11ea4a75e148cb841bb3cf653ad5d416a24d21e202e36bb50e0000 00000ffffffff46d1a5326b3b47ac784aa7b839505ff58b03c78b1abd19c2dcc61aa822e0a2dd9e 01000000ffffffff0101000000000000001976a914a86e8ee2a05a44613904e18132e49b2448adc4e688ac00000000

Which is an unsigned transaction in hex. I've bolded the two parts you need to modify by hand:

(0) The "1" which is the value of the output in satoshis, the number is little endian which is why most of the 0s come after it.  Change that 1 to a zero.

(1) The long part beginning with 1976a914...88ac. This is the scriptPubkey that the transaction pays to.  We replace that with 016a which is a 1 byte script (thus the 01) containing OP_RETURN which is the 0x6a opcode. This tells bitcoin to not save an output to the database.

With these two modifications all the coin value gets consolidated into the miner's fees and the global bitcoin database is cleaned up:

The result is:
0100000002f5803f35e4b911e11ea4a75e148cb841bb3cf653ad5d416a24d21e202e36bb50e0000 00000ffffffff46d1a5326b3b47ac784aa7b839505ff58b03c78b1abd19c2dcc61aa822e0a2dd9e 01000000ffffffff010000000000000000016a00000000

Which we can decode:

$ bitcoind decoderawtransaction 0100000002f5803f35e4b911e11ea4a75e148cb841bb3cf653ad5d416a24d21e202e36bb50e0000 00000ffffffff46d1a5326b3b47ac784aa7b839505ff58b03c78b1abd19c2dcc61aa822e0a2dd9e 01000000ffffffff010000000000000000016a00000000
{
    "txid" : "b147506ef23be7c7e8e0169b0aadf0bd1942d8acb9e31b48b0a1b904bf15425e",
    "version" : 1,
    "locktime" : 0,
    "vin" : [
        {
            "txid" : "50bb362e201ed2246a415dad53f63cbb41b88c145ea7a41ee111b9e4353f80f5",
            "vout" : 224,
            "scriptSig" : {
                "asm" : "",
                "hex" : ""
            },
            "sequence" : 4294967295
        },
        {
            "txid" : "dda2e022a81ac6dcc219bd1a8bc7038bf55f5039b8a74a78ac473b6b32a5d146",
            "vout" : 414,
            "scriptSig" : {
                "asm" : "",
                "hex" : ""
            },
            "sequence" : 4294967295
        }
    ],
    "vout" : [
        {
            "value" : 0.00000000,
            "n" : 0,
            "scriptPubKey" : {
                "asm" : "OP_RETURN",
                "hex" : "6a",
                "type" : "nonstandard"
            }
        }
    ]
}


Now this just needs to be signed.

To sign it we need the scriptPubKeys and the private keys.

To get the scriptPubKeys you can run:


$ bitcoind getrawtransaction <txid> 1 | grep '"n" : <vout>,' -A 3 | grep hex


Substituting the txid and vout.

All said and done, we sign our transaction hex using the scriptPubKeys and private keys in an


$ bitcoind signrawtransaction 0100000002f5803f35e4b911e11ea4a75e148cb841bb3cf653ad5d416a24d21e202e36bb50e0000 00000ffffffff46d1a5326b3b47ac784aa7b839505ff58b03c78b1abd19c2dcc61aa822e0a2dd9e 01000000ffffffff010000000000000000016a00000000 '[{"txid":"50bb362e201ed2246a415dad53f63cbb41b88c145ea7a41ee111b9e4353f80f5","vout":224,"scriptPubKey":"76a914f2b461e18eaeeb834e8964a0f6f46abfa5a493cf88ac"},{"txid":"dda2e022a81ac6dcc219bd1a8bc7038bf55f5039b8a74a78ac473b6b32a5d146","vout":414,"scriptPubKey":"76a9146adad08db0e0169c5db5b232e0cbe46af4e27fe288ac"}]' '["5KR8CRg662edTqU4AmPKEAVbg8Qj9RA1WbY6MNzb64T4kAyzDLV","5KjV1dJE58aFPB5HvTs8nbuQe8r8fUvHFEh3Pu8hQ8A7qSChEsi"]'  "NONE|ANYONECANPAY"


The final "NONE|ANYONECANPAY" uses the none and anyonecanpay sighash flags so that in theory the miner could merge this transaction with other cleanup transactions, it basically creates a signature that gives away these coins to anyone. You DONT want to use that option on normal spends of your own coins.

Which will return:


{
    "hex" : "0100000002f5803f35e4b911e11ea4a75e148cb841bb3cf653ad5d416a24d21e202e36bb50e0000 0008c493046022100fd91365fb7b652676a9baf0ff38970fc4adef66dc0d481985ad8ccd85a6762 6b022100b9c801ea7ed0efc93fa6f95d60cff4dbf476f276d80fdfa11e57356ddf46be928241046 a69146ba92ba33073caa21e74ebdc630813c9062281807ca6071bf6a83818ba8daa3836857154cb 6d7e036c9e36d1f67e75a5327b80b34761fd434ee067c61bffffffff46d1a5326b3b47ac784aa7b 839505ff58b03c78b1abd19c2dcc61aa822e0a2dd9e0100008c493046022100d4661ae28ddf7604 986b86de06b945600ae059a123c5c791202bdc63da4b7e6a022100a1ea94cacd5fa97f2435137da 8665fbd952507ad22e727567b3fb7fcdaeeb4348241040ace5fddc113ff9689496ea9abc30620d5 b032286df28e1a20cfeca112cf1c27050dacbc9de5dced5803b2d221f1c5163e4f0556b1f48e631 9cb2351dc3b347bffffffff010000000000000000016a00000000",
    "complete" : true
}


And the complete says the transaction is ready to send.

You can send it with sendrawtransaction <hex signed output>

If you don't want to go through the manual hex editing to get the transaction made into an OP_RETURN,  then at least please groom up multiple of these outputs into a payment to yourself...  the dust does you and no one else any good.

Congrats, you've now defragmented the Bitcoin global database a little bit. Have fun.

[Cablez]

I am sorry to drag this a bit off topic but seeing as I am not technically versed in these matters I was wondering.  I understand that these 'attacks' are on address/keypairs that are generated from in this case simple words mostly related to brainwallets.  What mechanisms are contained in the QT client that prevent simple brute forcing of address/keypairs or to put it another way how are secure addresses/keys generated in the QT client? Thanks

[gmaxwell]

I am sorry to drag this a bit off topic but seeing as I am not technically versed in these matters I was wondering.  I understand that these 'attacks' are on address/keypairs that are generated from in this case simple words mostly related to brainwallets.  What mechanisms are contained in the QT client that prevent simple brute forcing of address/keypairs or to put it another way how are secure addresses/keys generated in the QT client? Thanks

The QT client does not support "brainwallets" and its developers (as is the case for all the other compentently created wallet software) aggressively reject them.  Private keys in Bitcoin-QT are are 256 bits of cryptographically strong random data. Brute force searching to obtain one on a non-reversable classical computer is computation in the realm of "Step 1. first convert the local solar system to energy".

[Cablez]

Thanks very much gmaxwell.  That is what I had assumed was the case. So this is really about shortcuts taken to create addresses that could be recreated fairly easily.  Maybe the thread title is a tad misleading.

[bitcoindigi]

please rename the topic to dictionary attack againt brainwallets. sounds less stupid that way, OP.

[gmaxwell]

Maybe I am wrong but I don't think any wallet currently being used uses actual random data (such as input from a true random number generator).

No, Bitcoin-QT uses input from truly random sources (the operating system's true rng inputs and its own timing noise measurements, passed through cryptographic hardening just in case). AFAIK all other local client wallets do the same.

People have been trying to analyze patters in the way old blocks are mined so flaws in the private key generation algorithms could possibly be analyzed in a similar manner.

None of the things being analyzed in those discussions are actually (pseudo-)random things at all. E.g. the nonce used in mining is just a counter.

[crazy_rabbit]

please rename the topic to dictionary attack againt brainwallets. sounds less stupid that way, OP.

I'd like to rename it to: Stupidly short passwords strike again. It's not an attack if your brainwallet is the word "love". It's just stupid.

[crazy_rabbit]

Maybe I am wrong but I don't think any wallet currently being used uses actual random data (such as input from a true random number generator).

No, Bitcoin-QT uses input from truly random sources (the operating system's true rng inputs and its own timing noise measurements, passed through cryptographic hardening just in case). AFAIK all other local client wallets do the same.

People have been trying to analyze patters in the way old blocks are mined so flaws in the private key generation algorithms could possibly be analyzed in a similar manner.

None of the things being analyzed in those discussions are actually (pseudo-)random things at all. E.g. the nonce used in mining is just a counter.

It you can get true random numbers from these processes then why do companies make specialized random number generator cards?  Once company advertises that Satoshi dice uses their system.

http://en.wikipedia.org/wiki/Comparison_of_hardware_random_number_generators

Because sometimes, Like in the case of android- they are indeed: not random. Tricky tricky.

[gmaxwell]

It you can get true random numbers from these processes then why do companies make specialized random number generator cards?  Once company advertises that Satoshi dice uses their system.

Primarily because their throughput is relatively low. E.g. hundreds of bits per second.  There are applications where you want megabits of random data.

As far as Satoshi dice goes... thats pretty funny.  SDice's system is not random, their proof of faithful behavior requires that they be deterministic.

Because sometimes, Like in the case of android- they are indeed: not random. Tricky tricky.

Android's OS random numbers were plenty random... their libraries were mishandling them.

[cypherdoc]

gmaxwell,

thx for contributing so much to our overall understanding of this problem.