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packet.go
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packet.go
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package pgp
import "encoding/binary"
// EncodePacket encodes a binary Packet according to the generic OpenPGP
// packet encoding protocol.
//
// https://www.ietf.org/archive/id/draft-ietf-openpgp-rfc4880bis-10.html#section-4.2
func EncodePacket(tag PacketTag, payload []byte) []byte {
payloadSize := len(payload)
lengthEncoded := packetLengthEncode(payloadSize)
encoded := make([]byte, 1+len(lengthEncoded)+payloadSize)
encoded[0] = 0b11000000 | byte(tag)
copy(encoded[1:], lengthEncoded)
copy(encoded[1+len(lengthEncoded):], payload)
return encoded
}
func packetLengthEncode(payloadSize int) []byte {
if payloadSize <= 191 {
return []byte{byte(payloadSize)}
}
if payloadSize <= 8383 {
k := payloadSize - 192
return []byte{byte(k>>8) + 192, byte(k)}
}
lengthEncoded := []byte{0xFF, 0, 0, 0, 0}
binary.BigEndian.PutUint32(lengthEncoded[1:], uint32(payloadSize))
return lengthEncoded
}