sha256.go

Documentation: crypto/sha256

     1  // Copyright 2009 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // Package sha256 implements the SHA224 and SHA256 hash algorithms as defined
     6  // in FIPS 180-4.
     7  package sha256
     8  
     9  import (
    10  	"crypto"
    11  	"crypto/internal/boring"
    12  	"crypto/internal/fips140/sha256"
    13  	"hash"
    14  )
    15  
    16  func init() {
    17  	crypto.RegisterHash(crypto.SHA224, New224)
    18  	crypto.RegisterHash(crypto.SHA256, New)
    19  }
    20  
    21  // The size of a SHA256 checksum in bytes.
    22  const Size = 32
    23  
    24  // The size of a SHA224 checksum in bytes.
    25  const Size224 = 28
    26  
    27  // The blocksize of SHA256 and SHA224 in bytes.
    28  const BlockSize = 64
    29  
    30  // New returns a new [hash.Hash] computing the SHA256 checksum. The Hash
    31  // also implements [encoding.BinaryMarshaler], [encoding.BinaryAppender] and
    32  // [encoding.BinaryUnmarshaler] to marshal and unmarshal the internal
    33  // state of the hash.
    34  func New() hash.Hash {
    35  	if boring.Enabled {
    36  		return boring.NewSHA256()
    37  	}
    38  	return sha256.New()
    39  }
    40  
    41  // New224 returns a new [hash.Hash] computing the SHA224 checksum. The Hash
    42  // also implements [encoding.BinaryMarshaler], [encoding.BinaryAppender] and
    43  // [encoding.BinaryUnmarshaler] to marshal and unmarshal the internal
    44  // state of the hash.
    45  func New224() hash.Hash {
    46  	if boring.Enabled {
    47  		return boring.NewSHA224()
    48  	}
    49  	return sha256.New224()
    50  }
    51  
    52  // Sum256 returns the SHA256 checksum of the data.
    53  func Sum256(data []byte) [Size]byte {
    54  	if boring.Enabled {
    55  		return boring.SHA256(data)
    56  	}
    57  	h := New()
    58  	h.Write(data)
    59  	var sum [Size]byte
    60  	h.Sum(sum[:0])
    61  	return sum
    62  }
    63  
    64  // Sum224 returns the SHA224 checksum of the data.
    65  func Sum224(data []byte) [Size224]byte {
    66  	if boring.Enabled {
    67  		return boring.SHA224(data)
    68  	}
    69  	h := New224()
    70  	h.Write(data)
    71  	var sum [Size224]byte
    72  	h.Sum(sum[:0])
    73  	return sum
    74  }
    75
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