I tried running on my laptops ( AMD A6-3420M APU with HD Graphics AMD Radeon HD 6520G ) - getting an error.

(...)This fork https://github.com/pikachunakapika/BitCrack
Code:
-r, --random
    Each point will start in random KEYSPACE

This software does support such feature.

(post moved from bitcointalk.org/index.php?topic=5112311.msg51532763#msg51532763)

FAQ, How to recover a bitcoin PaperWallet using BitCrack.

We need a program
github.com/brichard19/BitCrack
Our task is to correctly specify the options "--keyspace" and "--stride".

Show how to recover


1) Calculate "--keyspace"

The private key of the paper wallet is in WIF format (base58check encoding).
We need to convert it to HEX format (base16 encoding)
For this we will use an online converter, for example
brainwalletx.github.io/#converter



Request the key(1) into the converter
"Source Text"->"5KVzbojiLku11111sKr6W9prrHx4XYfzjwsstfqjdembMEUsY42"
"Source Encoding"->"Base58"
Response
"Convert To"->"Hex"
"Result"->"80dddb314fa49158b8a43cae43cc017003a9ce0b2c43b407c4cbbb533d532a64a4186b7dab"
Save the number(1) in a notepad
80dddb314fa49158b8a43cae43cc017003a9ce0b2c43b407c4cbbb533d532a64a4186b7dab

Request the key(2) into the converter
"Source Text"->"5KVzbojiLku11112sKr6W9prrHx4XYfzjwsstfqjdembMEUsY42"
"Source Encoding"->"Base58"
Response
"Convert To"->"Hex"
"Result"->"80dddb314fa49158b8a43cceec129f5caa5f74de940f749841d3a1f8959aa342cc186b7dab"
Save the number(2) in a notepad
80dddb314fa49158b8a43cceec129f5caa5f74de940f749841d3a1f8959aa342cc186b7dab

Request the key(3) into the converter
"Source Text"->"5KVzbojiLkuzzzzzsKr6W9prrHx4XYfzjwsstfqjdembMEUsY42"
"Source Encoding"->"Base58"
Response
"Convert To"->"Hex"
"Result"->"80dddb314fa4915db64236699367f258926fcbd827398fc02deccb5d58bc12a77c186b7dab"
Save the number(3) in a notepad
80dddb314fa4915db64236699367f258926fcbd827398fc02deccb5d58bc12a77c186b7dab


We remove the left 2 digits ("80" is a bitcoin network label)
(1')dddb314fa49158b8a43cae43cc017003a9ce0b2c43b407c4cbbb533d532a64a4186b7dab
(2')dddb314fa49158b8a43cceec129f5caa5f74de940f749841d3a1f8959aa342cc186b7dab
(3')dddb314fa4915db64236699367f258926fcbd827398fc02deccb5d58bc12a77c186b7dab
Save the number(1') and the number(2') (they are needed to get "--stride")

We remove the right 8 digits ("186b7dab" - this is the checksum base58check)
(1'')dddb314fa49158b8a43cae43cc017003a9ce0b2c43b407c4cbbb533d532a64a4
(2'') for "--keyspace" number(2'') is not needed, skip
(3'')dddb314fa4915db64236699367f258926fcbd827398fc02deccb5d58bc12a77c

ATTENTION!
If your WIF key starts with "5" - this is an uncompressed key, and you can skip this warning.
If your WIF key starts with "L" or "K" - this is a compressed key, read the warning.
WIF "L"/"K" compressed keys are labeled "01" before the checksum - this also needs to be removed.
Ie, we remove the right 10 digits ("01" + 8 digit checksum base58check)

In fact, the number(1'') and number(3'') is the range of candidates for private keys in HEX.
Then the option "--keyspace (1''):(3'')" like


2) Calculate "--stride".

Convert number(1') and number(2') to DEC (base10 encoding)

Request the key(1') into the converter
"Source Text"->"dddb314fa49158b8a43cae43cc017003a9ce0b2c43b407c4cbbb533d532a64a4186b7dab"
"Source Encoding"->"Hex"
Response
"Convert To"->"Dec"
"Result"->"4309931794287609088053274827537810492913374270149990123844761122944746242931016 15414699"
Save the number(1''') in a notepad
4309931794287609088053274827537810492913374270149990123844761122944746242931016 15414699

Request the key(2') into the converter
"Source Text"->"dddb314fa49158b8a43cceec129f5caa5f74de940f749841d3a1f8959aa342cc186b7dab"
"Source Encoding"->"Hex"
Response
"Convert To"->"Dec"
"Result"->"4309931794287609088053275352320830782839823951879774905331246684460802851879681 94018731"
Save the number(2''') in a notepad
4309931794287609088053275352320830782839823951879774905331246684460802851879681 94018731

Why do we need the (1''') and (2''') in DEC? We need the difference (2')-(1') (not all calculators can count in hex)
For this, we will use an online high precision calculator, for example
www.ttmath.org/online_calculator
subtract from the larger (2''') the smaller (1'''),
i.e
52478302028992644968172978478148648556151605660894866578604032

Convert  to HEX

Request into the converter
"Source Text"->"52478302028992644968172978478148648556151605660894866578604032"
"Source Encoding"->"Dec"
Response
"Convert To"->"Hex"
"Result"->"20a8469deca6b5a6d367cbc0907d07e6a5584778de2800000000"

If your WIF key starts with "5" - we remove 8 digits from the right.
If your WIF key starts with "L" or "K" - we remove 10 numbers from the right.
20a8469deca6b5a6d367cbc0907d07e6a5584778de28

now option "--stride" as


3) Run BitCrack and restore PrivateKey



4) BitCrack Performance Tips.
BitCrack may not optimally calculate the -t and -p parameters (halving the speed).
run with the option "--continue sess.txt", any address, for example
xxBitCrack --continue sess.txt 17GD2bc5b7SvU7bzN7CYUSc6h4zBJ36Rx6
wait a little longer than a minute until the file of saving the progress will not be created, turn off;
open sess.txt, for example, "threads = 256" (this is the -t option) and "points = 32" (this is the -p option)
try to double the value, the speed should double;
remember them and always add when running BitCrack, for example
xxBitCrack -t 512 -p 64 17GD2bc5b7SvU7bzN7CYUSc6h4zBJ36Rx6


5) Repeat the calculations for the compressed key



"Base58"->"Hex"
(1)80dddb31430a12ceca48afa7302db7c16d048111b4490ef5aba1c538656e935576019027ecb6
(2)80dddb31430a12cfebbe7a4306570c1dbb22845e0aa8ec5e2fc70d1c25a48956f0019027ecb6
(3)80dddb316f464e913be304a3096441652fbe6bb3ee73e4b2dd88117af6a472823c019027ecb6

(1')dddb31430a12ceca48afa7302db7c16d048111b4490ef5aba1c538656e935576019027ecb6
(2')dddb31430a12cfebbe7a4306570c1dbb22845e0aa8ec5e2fc70d1c25a48956f0019027ecb6
(3')dddb316f464e913be304a3096441652fbe6bb3ee73e4b2dd88117af6a472823c019027ecb6

(1'')dddb31430a12ceca48afa7302db7c16d048111b4490ef5aba1c538656e935576
(2'') for "--keyspace" number(2'') is not needed, skip
(3'')dddb316f464e913be304a3096441652fbe6bb3ee73e4b2dd88117af6a472823c


(1')"Hex"->"Dec"
"Source Text"->"dddb31430a12ceca48afa7302db7c16d048111b4490ef5aba1c538656e935576019027ecb6"
"Result"->"1103342535601602776525285853177912161262361522527439740718572909944271817096236 43576200374"

(2')"Hex"->"Dec"
"Source Text"->"dddb31430a12cfebbe7a4306570c1dbb22845e0aa8ec5e2fc70d1c25a48956f0019027ecb6"
"Result"->"1103342535601602796503089304906835914569619353461138982851022867509637813984017 46502937782"

(2')-(1')
1103342535601602796503089304906835914569619353461138982851022867509637813984017 46502937782
-
1103342535601602776525285853177912161262361522527439740718572909944271817096236 43576200374
=
The result is:
1.997780345172892375330725783093369924213244995756536599688778102926737408e+72
i.e
1997780345172892375330725783093369924213244995756536599688778102926737408

"Source Text"->"1997780345172892375330725783093369924213244995756536599688778102926737408"
"Dec"->"Hex"
"Result"->"012175ca9bd629545c4e1e034c565fdd68842547e3c035f6017a0000000000"

012175ca9bd629545c4e1e034c565fdd68842547e3c035f6017a

//full key = "5Hvqe4cm3iaHiaVvyyRj2vEQGY2kR23Q987NZ1BroCExQb3Hbfg";
address = "1HfPVDokgJQMtcT1d9qUt7UAEpfZyUhH1V";
key = "5Hvqe4cm3iaHiaVvyyRj2vEQGY????3Q987NZ1BroCExQb3Hbfg";

(first) 5Hvqe4cm3iaHiaVvyyRj2vEQGY11113Q987NZ1BroCExQb3Hbfg
(second) 5Hvqe4cm3iaHiaVvyyRj2vEQGY11123Q987NZ1BroCExQb3Hbfg
(last) 5Hvqe4cm3iaHiaVvyyRj2vEQGYzzzz3Q987NZ1BroCExQb3Hbfg

(1) 800ee0f755f620249a6075b9511db7756e74c5ceb29bb48f2a1db0772fb0722c0d447e9fab
(2) 800ee0f755f620249a6075b9511db7756e74c5ceb2a3cdb2a956476a22bc2a5edb821e9fab
(3) 800ee0f755f620249a6075b9511db7756e74cb450feba4a247ac02d21afd23ed4800de9fab

(1') 0ee0f755f620249a6075b9511db7756e74c5ceb29bb48f2a1db0772fb0722c0d447e9fab
(2') 0ee0f755f620249a6075b9511db7756e74c5ceb2a3cdb2a956476a22bc2a5edb821e9fab
(3') 0ee0f755f620249a6075b9511db7756e74cb450feba4a247ac02d21afd23ed4800de9fab

(1'') 0ee0f755f620249a6075b9511db7756e74c5ceb29bb48f2a1db0772fb0722c0d
(2'') 0ee0f755f620249a6075b9511db7756e74c5ceb2a3cdb2a956476a22bc2a5edb
(3'') 0ee0f755f620249a6075b9511db7756e74cb450feba4a247ac02d21afd23ed48


--keyspace 0ee0f755f620249a6075b9511db7756e74c5ceb29bb48f2a1db0772fb0722c0d:0ee0f755f620249a6075b9511db7756e74cb450feba4a247ac02d21afd23ed48

(1''') 28904531490897711561887749949132137249603104743452438178887896886416998027619028869035
(2''') 28904531490897711561887749949132137249603104743463202530239465997930007122425245769643

difference(2''')-(1'''): 10764351351569111513009094806216900608

--stride 0819237f3896f2f30bb832ce

.\xxBitCrack -u --keyspace 0ee0f755f620249a6075b9511db7756e74c5ceb29bb48f2a1db0772fb0722c0d:0ee0f755f620249a6075b9511db7756e74cb450feba4a247ac02d21afd23ed48  --stride 819237f3896f2f30bb832ce  1HfPVDokgJQMtcT1d9qUt7UAEpfZyUhH1V

[Info] Compression: uncompressed
[Info] Starting at: 0EE0F755F620249A6075B9511DB7756E74C5CEB29BB48F2A1DB0772FB0722C0D
[Info] Ending at:   0EE0F755F620249A6075B9511DB7756E74CB450FEBA4A247AC02D21AFD23ED48
[Info] Counting by: 00000000000000000000000000000000000000000819237F3896F2F30BB832CE
[Info] Compiling OpenCL kernels...
[Info] Initializing Ellesmere
(...)
[Info] 100.0%
[Info] Done
[Info] Reached end of keyspace

If you know the public key (not the address) and the first ~ 180 bits of the private key, it is possible to retrieve the other 70 / 80 bits using smarter ways than brute force attack.

But AFAIK this software don't support such feature.