mirror of https://github.com/status-im/go-waku.git
49 lines
1.0 KiB
Go
49 lines
1.0 KiB
Go
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package noise
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import (
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"errors"
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)
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// PKCS7_Pad pads a payload according to PKCS#7 as per
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// RFC 5652 https://datatracker.ietf.org/doc/html/rfc5652#section-6.3
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func PKCS7_Pad(payload []byte, paddingSize int) ([]byte, error) {
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if paddingSize >= 256 {
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return nil, errors.New("invalid padding size")
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}
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k := paddingSize - (len(payload) % paddingSize)
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var padVal int
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if k != 0 {
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padVal = k
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} else {
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padVal = paddingSize
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}
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padding := make([]byte, padVal)
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for i := range padding {
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padding[i] = byte(padVal)
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}
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return append(payload, padding...), nil
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}
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// PKCS7_Unpad unpads a payload according to PKCS#7 as per
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// RFC 5652 https://datatracker.ietf.org/doc/html/rfc5652#section-6.3
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func PKCS7_Unpad(payload []byte, paddingSize int) ([]byte, error) {
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if paddingSize >= 256 {
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return nil, errors.New("invalid padding size")
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}
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if len(payload) == 0 {
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return nil, nil // empty payload
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}
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high := len(payload) - 1
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k := payload[high]
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unpadded := payload[0:(high + 1 - int(k))]
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return unpadded, nil
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}
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