yaole
39 lines
961 B
Go
39 lines
961 B
Go
package sm2m
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import (
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"math/big"
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"xdx.jelly/xgcl/gmath"
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"xdx.jelly/xgcl/sm/sm2"
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)
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/*
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导入加密密钥de，由sm2签名密钥来解密sm2加密密钥保护结构。
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解密de后拆分也同签名密钥拆分
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(1+de)^{-1} = de_c*de_s
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为了加解密函数一致
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*/
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// ServerDec 服务端计算(serverKey)^(-1)*C1，使用签名密钥解密加密密钥保护结构
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func ServerImportKey(serverKey *sm2.PrivateKey, in []byte) ([]byte, error) {
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if len(in) < 2*sm2.ByteSize() {
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return []byte{}, ErrIndataError
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}
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x := new(big.Int)
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x.SetBytes(in[:sm2.ByteSize()])
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y := new(big.Int)
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y.SetBytes(in[sm2.ByteSize() : 2*sm2.ByteSize()])
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sInv := new(big.Int)
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sInv.Set(serverKey.D)
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sInv.ModInverse(sInv, sm2.OrderN())
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x, y = sm2.Curve256.ScalarMult(x, y, sInv.Bytes())
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out := make([]byte, 0, 2*sm2.ByteSize())
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out = append(out, gmath.BigIntToNByte(x, sm2.ByteSize())...)
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out = append(out, gmath.BigIntToNByte(y, sm2.ByteSize())...)
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return out, nil
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}
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