Calculating S from Public Keys and Message

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wolf_2020Member
Posts: 9 · Reputation: 229
#1Jan 21, 2018, 04:51 PM
Hey guys, I need some help with the S calculation. Here's the data I have: priv_publickey_XY = px: 0xbb6c1de01f36618ae05f7c183c22dfa8797e779f39537752c27e2dc045b0e694 py: 0x2f8af53270bf045f2258834b6dad7481ad6fca009d80f5b54697b08d104fc7b3 nonce_publickey_XY = px: 0xcabc3692f1f7ba75a8572dc5d270b35bcc00650534f6e5ecd6338e55355454d5 py: 0xafa7746c07a124cb59e190f00955952a7329591b805c4d9d04d34abe8a803a74 Message(z) = 0x9b076ad2fe6b2ce63acf4edf7fc82d5152d3c8bffb36b944da7a1cce038f544a I need to find S from these values... any ideas?
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madvaultNewbie
Posts: 6 · Reputation: 10
#2Jan 21, 2018, 10:12 PM
Looks like you're working with Schnorr signatures. From what I know, to find S: s = k + m*x Where m is the hashed message (probably using SHA256), x is your private key, and k is a randomly generated private key. To verify S, you can multiply it by G, the base point on the elliptic curve, using secp256k1 in Bitcoin. So it all checks out, just follow the math and you'll get your S. Anyone else got thoughts on this?
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