github.com/hxx258456/ccgo@v0.0.5-0.20230213014102-48b35f46f66f/sm4soft/padding/bloc_cryptor.go (about)

     1  // Copyright 2022 s1ren@github.com/hxx258456.
     2  
     3  /*
     4  sm4soft 是sm4的纯软实现，基于tjfoc国密算法库`tjfoc/gmsm`做了少量修改。
     5  对应版权声明: thrid_licenses/github.com/tjfoc/gmsm/版权声明
     6  */
     7  
     8  package padding
     9  
    10  import (
    11  	"crypto/cipher"
    12  	"io"
    13  )
    14  
    15  // P7BlockDecrypt 解密密文，并去除PKCS#7填充
    16  // decrypter: 块解密器
    17  // in: 密文输入流
    18  // out: 明文输出流
    19  func P7BlockDecrypt(decrypter cipher.BlockMode, in io.Reader, out io.Writer) error {
    20  	bufIn := make([]byte, 1024)
    21  	bufOut := make([]byte, 1024)
    22  	p7Out := NewPKCS7PaddingWriter(out, decrypter.BlockSize())
    23  	for {
    24  		n, err := in.Read(bufIn)
    25  		if err != nil && err != io.EOF {
    26  			return err
    27  		}
    28  		if n == 0 {
    29  			break
    30  		}
    31  		decrypter.CryptBlocks(bufOut, bufIn[:n])
    32  		_, err = p7Out.Write(bufOut[:n])
    33  		if err != nil {
    34  			return err
    35  		}
    36  	}
    37  	return p7Out.Final()
    38  }
    39  
    40  // P7BlockEnc 以PKCS#7填充模式填充原文，并加密输出
    41  // encrypter: 块加密器
    42  // in: 明文输入流
    43  // out: 密文输出流
    44  func P7BlockEnc(encrypter cipher.BlockMode, in io.Reader, out io.Writer) error {
    45  	bufIn := make([]byte, 1024)
    46  	bufOut := make([]byte, 1024)
    47  	p7In := NewPKCS7PaddingReader(in, encrypter.BlockSize())
    48  	for {
    49  		n, err := p7In.Read(bufIn)
    50  		if err != nil && err != io.EOF {
    51  			return err
    52  		}
    53  		if n == 0 {
    54  			break
    55  		}
    56  		encrypter.CryptBlocks(bufOut, bufIn[:n])
    57  		_, err = out.Write(bufOut[:n])
    58  		if err != nil {
    59  			return err
    60  		}
    61  	}
    62  	return nil
    63  }