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crypto/subtle/hkdf.go

@@ -1,55 +0,0 @@
-package subtle
-
-import (
-	"errors"
-	"fmt"
-	"io"
-
-	"golang.org/x/crypto/hkdf"
-)
-
-const (
-	// Minimum tag size in bytes. This provides minimum 80-bit security strength.
-	minTagSizeInBytes = uint32(10)
-)
-
-var errHKDFInvalidInput = errors.New("HKDF: invalid input")
-
-// validateHKDFParams validates parameters of HKDF constructor.
-func validateHKDFParams(hash string, _ uint32, tagSize uint32) error {
-	// validate tag size
-	digestSize, err := GetHashDigestSize(hash)
-	if err != nil {
-		return err
-	}
-	if tagSize > 255*digestSize {
-		return fmt.Errorf("tag size too big")
-	}
-	if tagSize < minTagSizeInBytes {
-		return fmt.Errorf("tag size too small")
-	}
-	return nil
-}
-
-// ComputeHKDF extracts a pseudorandom key.
-func ComputeHKDF(hashAlg string, key []byte, salt []byte, info []byte, tagSize uint32) ([]byte, error) {
-	keySize := uint32(len(key))
-	if err := validateHKDFParams(hashAlg, keySize, tagSize); err != nil {
-		return nil, fmt.Errorf("hkdf: %s", err)
-	}
-	hashFunc := GetHashFunc(hashAlg)
-	if hashFunc == nil {
-		return nil, fmt.Errorf("hkdf: invalid hash algorithm")
-	}
-	if len(salt) == 0 {
-		salt = make([]byte, hashFunc().Size())
-	}
-
-	result := make([]byte, tagSize)
-	kdf := hkdf.New(hashFunc, key, salt, info)
-	n, err := io.ReadFull(kdf, result)
-	if n != len(result) || err != nil {
-		return nil, fmt.Errorf("compute of hkdf failed")
-	}
-	return result, nil
-}