SHA加密算法

SHA：Secure Hash Algorithm

安全散列算法

 

 

与MD5算法极为相似。

长度不超过2^64位的字符串或二进制流，经过SHA-1编码后，生成一个160位的二进制串。

 

SHA-1算法也与MD5类似，都是把输入二进制串分成512位的块，把二进制串的位数存储在最后64位，二者之间填充为0，依次对每个块进行一些列高深的数学运算，最后得到一个160位的二进制串。

 

通常表示为40个十六进制数字。

 

例：

SHA-1("")=da39a3ee5e6b4b0d3255bfef95601890afd80709

SHA-1("hello world!")=430ce34d020724ed75a196dfc2ad67c77772d169

 

SHA算法也是不可逆的。

 

从SHA-1的算法可以简单看出，SHA-1安全性比MD5稍高(160位VS128位)，但算法需要时间SHA-1稍慢。

 

在Java中可以简单地通过引用commons-codec来取得sha-1。

/*
* If you do not have the ISO standard stdint.h header file, then you
* must typdef the following:
* name meaning
* uint32_t unsigned 32 bit integer
* uint8_t unsigned 8 bit integer (i.e., unsigned char)
* int_least16_t integer of >= 16 bits
*
*/

typedef unsigned int uint32_t;
typedef unsigned char uint8_t;
typedef short int int_least16_t;

#ifndef _SHA_enum_
#define _SHA_enum_
enum
{
    shaSuccess = 0,
    shaNull,         /* Null pointer parameter */
    shaInputTooLong, /* input data too long */
    shaStateError    /* called Input after Result */
};
#endif
#define SHA1HashSize 20
/*
* This structure will hold context information for the SHA-1
* hashing operation
*/
typedef struct SHA1Context
{
    uint32_t Intermediate_Hash[SHA1HashSize/4]; /* Message Digest */
    uint32_t Length_Low; /* Message length in bits */
    uint32_t Length_High; /* Message length in bits */
    /* Index into message block array */
    int_least16_t Message_Block_Index;
    uint8_t Message_Block[64]; /* 512-bit message blocks */
    int Computed; /* Is the digest computed? */
    int Corrupted; /* Is the message digest corrupted? */
} SHA1Context;


/*
* Function Prototypes
*/

int SHA1Reset( SHA1Context *);
int SHA1Input( SHA1Context *,const uint8_t *,unsigned int);
int SHA1Result( SHA1Context *,uint8_t Message_Digest[SHA1HashSize]);



/*
* sha1.c
*
* Description:
* This file implements the Secure Hashing Algorithm 1 as
* defined in FIPS PUB 180-1 published April 17, 1995.
*
* The SHA-1, produces a 160-bit message digest for a given
* data stream. It should take about 2**n steps to find a
* message with the same digest as a given message and
* 2**(n/2) to find any two messages with the same digest,
* when n is the digest size in bits. Therefore, this
* algorithm can serve as a means of providing a
* "fingerprint" for a message.
*
* Portability Issues:
* SHA-1 is defined in terms of 32-bit "words". This code
* uses  (included via "sha1.h" to define 32 and 8
* bit unsigned integer types. If your C compiler does not
* support 32 bit unsigned integers, this code is not
* appropriate.
*
* Caveats:
* SHA-1 is designed to work with messages less than 2^64 bits
* long. Although SHA-1 allows a message digest to be generated
* for messages of any number of bits less than 2^64, this
* implementation only works with messages with a length that is
* a multiple of the size of an 8-bit character.
*
*/


#ifdef __cplusplus
extern "C"
{
#endif

/*
* Define the SHA1 circular left shift macro
*/
#define SHA1CircularShift(bits,word) \
    (((word) << (bits)) | ((word) >> (32-(bits))))
/* Local Function Prototyptes */
void SHA1PadMessage(SHA1Context *);
void SHA1ProcessMessageBlock(SHA1Context *);
/*
* SHA1Reset
*
* Description:
* This function will initialize the SHA1Context in preparation
* for computing a new SHA1 message digest.
*
* Parameters:
* context: [in/out]
* The context to reset.
*
* Returns:
* sha Error Code.
*
*/
int SHA1Reset(SHA1Context *context)//初始化状态
{
    if (!context)
    {
        return shaNull;
    }
    context->Length_Low = 0;
    context->Length_High = 0;
    context->Message_Block_Index = 0;
    context->Intermediate_Hash[0] = 0x67452301;//取得的HASH结果（中间数据）
    context->Intermediate_Hash[1] = 0xEFCDAB89;
    context->Intermediate_Hash[2] = 0x98BADCFE;
    context->Intermediate_Hash[3] = 0x10325476;
    context->Intermediate_Hash[4] = 0xC3D2E1F0;
    context->Computed = 0;
    context->Corrupted = 0;
    return shaSuccess;
}


/*
* SHA1Result
*
* Description:
* This function will return the 160-bit message digest into the
* Message_Digest array provided by the caller.
* NOTE: The first octet of hash is stored in the 0th element,
* the last octet of hash in the 19th element.
*
* Parameters:
* context: [in/out]
* The context to use to calculate the SHA-1 hash.
* Message_Digest: [out]
* Where the digest is returned.
*
* Returns:
* sha Error Code.
*
*/
int SHA1Result( SHA1Context *context,uint8_t Message_Digest[SHA1HashSize])
{
    int i;
    if (!context || !Message_Digest)
    {
        return shaNull;
    }
    if (context->Corrupted)
    {
        return context->Corrupted;
    }
    if (!context->Computed)
    {
        SHA1PadMessage(context);
        for(i=0; i<64; ++i)
        {
            /* message may be sensitive, clear it out */
            context->Message_Block[i] = 0;
        }
        context->Length_Low = 0; /* and clear length */
        context->Length_High = 0;
        context->Computed = 1;
    }
    for(i = 0; i < SHA1HashSize; ++i)
    {
        Message_Digest[i] = context->Intermediate_Hash[i>>2]
        >> 8 * ( 3 - ( i & 0x03 ) );
    }
    return shaSuccess;
}


/*
* SHA1Input
*
* Description:
* This function accepts an array of octets as the next portion
* of the message.
*
* Parameters:
* context: [in/out]
* The SHA context to update
* message_array: [in]
* An array of characters representing the next portion of
* the message.
* length: [in]
* The length of the message in message_array
*
* Returns:
* sha Error Code.
*
*/

int SHA1Input( SHA1Context *context,const uint8_t *message_array,unsigned length)
{
    if (!length)
    {
        return shaSuccess;
    }
    if (!context || !message_array)
    {
        return shaNull;
    }
    if (context->Computed)
    {
        context->Corrupted = shaStateError;
        return shaStateError;
    }
    if (context->Corrupted)
    {
        return context->Corrupted;
    }
    while(length-- && !context->Corrupted)
    {
        context->Message_Block[context->Message_Block_Index++] =
            (*message_array & 0xFF);
        context->Length_Low += 8;
        if (context->Length_Low == 0)
        {
            context->Length_High++;
            if (context->Length_High == 0)
            {
                /* Message is too long */
                context->Corrupted = 1;
            }
        }
        if (context->Message_Block_Index == 64)
        {
            SHA1ProcessMessageBlock(context);
        }
        message_array++;
    }
    return shaSuccess;
}

/*
* SHA1ProcessMessageBlock
*
* Description:
* This function will process the next 512 bits of the message
* stored in the Message_Block array.
*
* Parameters:
* None.
*
* Returns:
* Nothing.
*
* Comments:
* Many of the variable names in this code, especially the
* single character names, were used because those were the
* names used in the publication.
*
*/

void SHA1ProcessMessageBlock(SHA1Context *context)
{
    const uint32_t K[] = { /* Constants defined in SHA-1 */
        0x5A827999,
        0x6ED9EBA1,
        0x8F1BBCDC,
        0xCA62C1D6
    };
    int t; /* Loop counter */
    uint32_t temp; /* Temporary word value */
    uint32_t W[80]; /* Word sequence */
    uint32_t A, B, C, D, E; /* Word buffers */
    /*
    * Initialize the first 16 words in the array W
    */
    for(t = 0; t < 16; t++)
    {
        W[t] = context->Message_Block[t * 4] << 24;
        W[t] |= context->Message_Block[t * 4 + 1] << 16;
        W[t] |= context->Message_Block[t * 4 + 2] << 8;
        W[t] |= context->Message_Block[t * 4 + 3];
    }
    for(t = 16; t < 80; t++)
    {
        W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
    }
    A = context->Intermediate_Hash[0];
    B = context->Intermediate_Hash[1];
    C = context->Intermediate_Hash[2];
    D = context->Intermediate_Hash[3];
    E = context->Intermediate_Hash[4];
    for(t = 0; t < 20; t++)
    {
                temp = SHA1CircularShift(5,A) +
                        ((B & C) | ((~B) & D)) + E + W[t] + K[0];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    for(t = 20; t < 40; t++)
    {
        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    for(t = 40; t < 60; t++)
    {
        temp = SHA1CircularShift(5,A) +
            ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    for(t = 60; t < 80; t++)
    {
        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    context->Intermediate_Hash[0] += A;
    context->Intermediate_Hash[1] += B;
    context->Intermediate_Hash[2] += C;
    context->Intermediate_Hash[3] += D;
    context->Intermediate_Hash[4] += E;
    context->Message_Block_Index = 0;
}


/*
* SHA1PadMessage
*
* Description:
* According to the standard, the message must be padded to an even
* 512 bits. The first padding bit must be a ’1’. The last 64
* bits represent the length of the original message. All bits in
* between should be 0. This function will pad the message
* according to those rules by filling the Message_Block array
* accordingly. It will also call the ProcessMessageBlock function
* provided appropriately. When it returns, it can be assumed that
* the message digest has been computed.
*
* Parameters:
* context: [in/out]
* The context to pad
* ProcessMessageBlock: [in]
* The appropriate SHA*ProcessMessageBlock function
* Returns:
* Nothing.
*
*/

void SHA1PadMessage(SHA1Context *context)
{
    /*
    * Check to see if the current message block is too small to hold
    * the initial padding bits and length. If so, we will pad the
    * block, process it, and then continue padding into a second
    * block.
    */
    if (context->Message_Block_Index > 55)
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while(context->Message_Block_Index < 64)
        {
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
        SHA1ProcessMessageBlock(context);
        while(context->Message_Block_Index < 56)
        {
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
    }
    else
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while(context->Message_Block_Index < 56)
        {
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
    }

    /*
    * Store the message length as the last 8 octets
    */
    context->Message_Block[56] = context->Length_High >> 24;
    context->Message_Block[57] = context->Length_High >> 16;
    context->Message_Block[58] = context->Length_High >> 8;
    context->Message_Block[59] = context->Length_High;
    context->Message_Block[60] = context->Length_Low >> 24;
    context->Message_Block[61] = context->Length_Low >> 16;
    context->Message_Block[62] = context->Length_Low >> 8;
    context->Message_Block[63] = context->Length_Low;
    SHA1ProcessMessageBlock(context);
}


#ifdef __cplusplus
}
#endif

/*
* sha1test.c
*
* Description:
* This file will exercise the SHA-1 code performing the three
* tests documented in FIPS PUB 180-1 plus one which calls
* SHA1Input with an exact multiple of 512 bits, plus a few
* error test checks.
*
* Portability Issues:
* None.
*
*/

#include 
#include 
#include 

/*
* 进行sha1算法运算
* @input 输入的字符串
* @output 输出的字符串
* @size 输入字符串长度
* return  0 成功，-1 失败
*/
int sha1(const char *input, uint8_t output[20], unsigned size)
{
    int i, err;
    SHA1Context sha;

    err = SHA1Reset(&sha);
    err = SHA1Input(&sha,(const unsigned char *) input, size);
    if (err){
        printf("SHA1Input Error %d.\n", err);
        return -1;
    }
    err = SHA1Result(&sha, output);
    if (err){
        printf("SHA1Result Error %d, could not compute message digest.\n",err );
        return -1;
    } 
    return 0;
}
int main()
{
    SHA1Context sha;
    int i, j, err, ret; 
    uint8_t Message_Digest[20];
    char buf[1024] = {0};

    printf("input:\n");
    scanf("%s", buf);
    printf("buf=%s\n",buf);
    ret = sha1(buf, Message_Digest, strlen(buf));
    if (ret == 0){
        printf("\n");
        for(i = 0; i < 20 ; ++i)
        {
            printf("%02x", Message_Digest[i]);
        }
        printf("\n");
    } else {
        printf("error\n");
    }

    return 0;
}