60 lines
1.3 KiB
Go
60 lines
1.3 KiB
Go
package api
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import (
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"bytes"
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"encoding/hex"
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"strconv"
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"strings"
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"github.com/ethereum/go-ethereum/crypto"
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)
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// RunAsync runs the specified function asynchronously.
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func RunAsync(f func() error) <-chan error {
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resp := make(chan error, 1)
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go func() {
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err := f()
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resp <- err
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close(resp)
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}()
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return resp
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}
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// HashMessage calculates the hash of a message to be safely signed by the keycard
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// The hash is calulcated as
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// keccak256("\x19Ethereum Signed Message:\n"${message length}${message}).
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// This gives context to the signed message and prevents signing of transactions.
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func HashMessage(message string) ([]byte, error) {
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buf := bytes.NewBufferString("\x19Ethereum Signed Message:\n")
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if value, ok := decodeHexStrict(message); ok {
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if _, err := buf.WriteString(strconv.Itoa(len(value))); err != nil {
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return nil, err
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}
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if _, err := buf.Write(value); err != nil {
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return nil, err
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}
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} else {
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if _, err := buf.WriteString(strconv.Itoa(len(message))); err != nil {
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return nil, err
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}
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if _, err := buf.WriteString(message); err != nil {
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return nil, err
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}
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}
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return crypto.Keccak256(buf.Bytes()), nil
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}
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func decodeHexStrict(s string) ([]byte, bool) {
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if !strings.HasPrefix(s, "0x") {
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return nil, false
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}
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value, err := hex.DecodeString(s[2:])
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if err != nil {
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return nil, false
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}
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return value, true
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}
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