📅 Original date posted:2015-10-03
📝 Original message:
>
>
> Ah, it looks like the problem is that libsec256k1 actually goes a step
> further and runs SHA256(y||x), where "x" is the value I'm getting and y
> is '\x02' is the y value is even and '\x03' if it's odd. If I try both,
> one of them turns out right:
>
> Secret1: d9946724c6bd8d5b58bdd2256a0251816a42f9707c794427a410075e4dbb199c
> Secret2: 105e0c04f0a910d72dcf2683c21903ba08cd8b225e4124afc41bb2341dc40f49
>
> Unfortunately openssl throws away y and just gives us x, so I'm not sure
> if I can work out the right secret directly. I guess I can run the HMAC
> twice and pick the value that worked?
>
> Okay, we'll see if we can get any further tomorrow.
>
> Cheers,
> aj
>
My open source library pycoin has a function that will give you Y from X,
so you can use that or just pilfer enough code to reproduce it (it's not
native, but it's not a very complex operation).
https://github.com/richardkiss/pycoin/blob/master/pycoin/ecdsa/ecdsa.py#L115
Richard
--
http://richardkiss.com/
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Richard Kiss [ARCHIVE] /
npub13e…kyqe7
2023-06-09 12:44:43
in reply to nevent1q…4jjn
Author Public Key
npub13erleydh06jnsdsz3y8xgza85h29g7kr6fus5ukx8j0f3pwyls3qrkyqe7Published at
2023-06-09 12:44:43Event JSON
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"content": "📅 Original date posted:2015-10-03\n📝 Original message:\n\u003e\n\u003e\n\u003e Ah, it looks like the problem is that libsec256k1 actually goes a step\n\u003e further and runs SHA256(y||x), where \"x\" is the value I'm getting and y\n\u003e is '\\x02' is the y value is even and '\\x03' if it's odd. If I try both,\n\u003e one of them turns out right:\n\u003e\n\u003e Secret1: d9946724c6bd8d5b58bdd2256a0251816a42f9707c794427a410075e4dbb199c\n\u003e Secret2: 105e0c04f0a910d72dcf2683c21903ba08cd8b225e4124afc41bb2341dc40f49\n\u003e\n\u003e Unfortunately openssl throws away y and just gives us x, so I'm not sure\n\u003e if I can work out the right secret directly. I guess I can run the HMAC\n\u003e twice and pick the value that worked?\n\u003e\n\u003e Okay, we'll see if we can get any further tomorrow.\n\u003e\n\u003e Cheers,\n\u003e aj\n\u003e\n\nMy open source library pycoin has a function that will give you Y from X,\nso you can use that or just pilfer enough code to reproduce it (it's not\nnative, but it's not a very complex operation).\n\nhttps://github.com/richardkiss/pycoin/blob/master/pycoin/ecdsa/ecdsa.py#L115\n\nRichard\n\n-- \nhttp://richardkiss.com/\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/lightning-dev/attachments/20151003/4c630e5d/attachment.html\u003e",
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