kdf/nist_sp800_56a.go
func DeriveConcatKDF(keydatalen int, sharedSecret, algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo []byte, h hash.Hash) []byte {
	
	otherInfo := arrays.Concat(algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo)
	
	keyLenBytes := keydatalen >> 3
	
	reps := int(math.Ceil(float64(keyLenBytes) / float64(h.Size())))
	
	if reps > MaxInt {
		panic("kdf.DeriveConcatKDF: too much iterations (more than 2^32-1).")
	}
	
	dk:=make([]byte, 0, keyLenBytes)
	
	for counter := 1;counter <= reps;counter++ {
		h.Reset()

		counterBytes:=arrays.UInt32ToBytes(uint32(counter))
						
		h.Write(counterBytes)
		h.Write(sharedSecret)		
		h.Write(otherInfo)
		
		dk = h.Sum(dk)
	}

	return dk[:keyLenBytes]	
}
func DeriveConcatKDF(keydatalen int, sharedSecret, algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo []byte, h hash.Hash) []byte {
	
	otherInfo := arrays.Concat(algId, partyUInfo, partyVInfo, suppPubInfo, suppPrivInfo)
	
	keyLenBytes := keydatalen >> 3
	
	reps := int(math.Ceil(float64(keyLenBytes) / float64(h.Size())))
	
	if reps > MaxInt {
		panic("kdf.DeriveConcatKDF: too much iterations (more than 2^32-1).")
	}
	
	dk:=make([]byte, 0, keyLenBytes)
	
	for counter := 1;counter <= reps;counter++ {
		h.Reset()

		counterBytes:=arrays.UInt32ToBytes(uint32(counter))
						
		h.Write(counterBytes)
		h.Write(sharedSecret)		
		h.Write(otherInfo)
		
		dk = h.Sum(dk)
	}

	return dk[:keyLenBytes]	
}
func DeriveConcatKDF ( keydatalen int , sharedSecret , algId , partyUInfo , partyVInfo , suppPubInfo , suppPrivInfo [ ] byte , h hash . Hash ) [ ] byte { otherInfo := arrays . Concat ( algId , partyUInfo , partyVInfo , suppPubInfo , suppPrivInfo ) keyLenBytes := keydatalen >> 3 reps := int ( math . Ceil ( float64 ( keyLenBytes ) / float64 ( h . Size ( ) ) ) ) if reps > MaxInt { panic ( " " ) } dk := make ( [ ] byte , 0 , keyLenBytes ) for counter := 1 ; counter <= reps ; counter ++ { h . Reset ( ) counterBytes := arrays . UInt32ToBytes ( uint32 ( counter ) ) h . Write ( counterBytes ) h . Write ( sharedSecret ) h . Write ( otherInfo ) dk = h . Sum ( dk ) } return dk [ : keyLenBytes ] }
// DeriveConcatKDF implements NIST SP 800-56A Concatenation Key Derivation Function. Derives 
// key material of keydatalen bits size given Z (sharedSecret), OtherInfo (AlgorithmID | 
// PartyUInfo | PartyVInfo | SuppPubInfo | SuppPrivInfo) and hash function
DeriveConcatKDF implements NIST SP 800 - 56A Concatenation Key Derivation Function . Derives key material of keydatalen bits size given Z ( sharedSecret ) OtherInfo ( AlgorithmID | PartyUInfo | PartyVInfo | SuppPubInfo | SuppPrivInfo ) and hash function