hmac.go

Documentation: cuelang.org/go/pkg/crypto/hmac

     1  // Copyright 2021 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package hmac implements the Keyed-Hash Message Authentication Code (HMAC) as
    16  // defined in U.S. Federal Information Processing Standards Publication 198.
    17  //
    18  // An HMAC is a cryptographic hash that uses a key to sign a message.
    19  // The receiver verifies the hash by recomputing it using the same key.
    20  package hmac
    21  
    22  import (
    23  	"crypto/hmac"
    24  	"crypto/md5"
    25  	"crypto/sha1"
    26  	"crypto/sha256"
    27  	"crypto/sha512"
    28  	"fmt"
    29  	"hash"
    30  )
    31  
    32  const (
    33  	MD5        = "MD5"
    34  	SHA1       = "SHA1"
    35  	SHA224     = "SHA224"
    36  	SHA256     = "SHA256"
    37  	SHA384     = "SHA384"
    38  	SHA512     = "SHA512"
    39  	SHA512_224 = "SHA512_224"
    40  	SHA512_256 = "SHA512_256"
    41  )
    42  
    43  // Sign returns the HMAC signature of the data, using the provided key and hash function.
    44  //
    45  // Supported hash functions: "MD5", "SHA1", "SHA224", "SHA256", "SHA384", "SHA512", "SHA512_224",
    46  // and "SHA512_256".
    47  func Sign(hashName string, key []byte, data []byte) ([]byte, error) {
    48  	hash, err := hashFromName(hashName)
    49  	if err != nil {
    50  		return nil, err
    51  	}
    52  	mac := hmac.New(hash, key)
    53  	mac.Write(data)
    54  	return mac.Sum(nil), nil
    55  }
    56  
    57  func hashFromName(hash string) (func() hash.Hash, error) {
    58  	switch hash {
    59  	case MD5:
    60  		return md5.New, nil
    61  	case SHA1:
    62  		return sha1.New, nil
    63  	case SHA224:
    64  		return sha256.New224, nil
    65  	case SHA256:
    66  		return sha256.New, nil
    67  	case SHA384:
    68  		return sha512.New384, nil
    69  	case SHA512:
    70  		return sha512.New, nil
    71  	case SHA512_224:
    72  		return sha512.New512_224, nil
    73  	case SHA512_256:
    74  		return sha512.New512_256, nil
    75  	}
    76  	return nil, fmt.Errorf("unsupported hash function")
    77  }
    78
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