gitee.com/ks-custle/core-gm@v0.0.0-20230922171213-b83bdd97b62c/sm4soft/padding/bloc_cryptor.go (about)

     1  // Copyright (c) 2022 zhaochun
     2  // core-gm is licensed under Mulan PSL v2.
     3  // You can use this software according to the terms and conditions of the Mulan PSL v2.
     4  // You may obtain a copy of Mulan PSL v2 at:
     5  //          http://license.coscl.org.cn/MulanPSL2
     6  // THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
     7  // See the Mulan PSL v2 for more details.
     8  
     9  /*
    10  sm4soft 是sm4的纯软实现，基于tjfoc国密算法库`tjfoc/gmsm`做了少量修改。
    11  对应版权声明: thrid_licenses/github.com/tjfoc/gmsm/版权声明
    12  */
    13  
    14  package padding
    15  
    16  import (
    17  	"crypto/cipher"
    18  	"io"
    19  )
    20  
    21  // P7BlockDecrypt 解密密文，并去除PKCS#7填充
    22  // decrypter: 块解密器
    23  // in: 密文输入流
    24  // out: 明文输出流
    25  func P7BlockDecrypt(decrypter cipher.BlockMode, in io.Reader, out io.Writer) error {
    26  	bufIn := make([]byte, 1024)
    27  	bufOut := make([]byte, 1024)
    28  	p7Out := NewPKCS7PaddingWriter(out, decrypter.BlockSize())
    29  	for {
    30  		n, err := in.Read(bufIn)
    31  		if err != nil && err != io.EOF {
    32  			return err
    33  		}
    34  		if n == 0 {
    35  			break
    36  		}
    37  		decrypter.CryptBlocks(bufOut, bufIn[:n])
    38  		_, err = p7Out.Write(bufOut[:n])
    39  		if err != nil {
    40  			return err
    41  		}
    42  	}
    43  	return p7Out.Final()
    44  }
    45  
    46  // P7BlockEnc 以PKCS#7填充模式填充原文，并加密输出
    47  // encrypter: 块加密器
    48  // in: 明文输入流
    49  // out: 密文输出流
    50  func P7BlockEnc(encrypter cipher.BlockMode, in io.Reader, out io.Writer) error {
    51  	bufIn := make([]byte, 1024)
    52  	bufOut := make([]byte, 1024)
    53  	p7In := NewPKCS7PaddingReader(in, encrypter.BlockSize())
    54  	for {
    55  		n, err := p7In.Read(bufIn)
    56  		if err != nil && err != io.EOF {
    57  			return err
    58  		}
    59  		if n == 0 {
    60  			break
    61  		}
    62  		encrypter.CryptBlocks(bufOut, bufIn[:n])
    63  		_, err = out.Write(bufOut[:n])
    64  		if err != nil {
    65  			return err
    66  		}
    67  	}
    68  	return nil
    69  }