SHA1.java

public class SHA1 {
    private final int[] abcde = {
            0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0
        };

    //  Summary data storage array  
    private int[] digestInt = new int[5];

    //  The calculation process for temporary data storage array  
    private int[] tmpData = new int[80];

    //  Calculates sha  -1 Summary  
    private int process_input_bytes(byte[] bytedata) {
        //  Keen understanding of constant  
        System.arraycopy(abcde, 0, digestInt, 0, abcde.length);

        //  Formatted input byte array, Supplement 10 and length data  
        byte[] newbyte = byteArrayFormatData(bytedata);

        //  Gets the data Digest calculation data cell number  
        int MCount = newbyte.length / 64;

        //  Cycling on each data cell for Digest calculation  
        for (int pos = 0; pos < MCount; pos++) {
            //  Each unit of data is converted to a 16 integer data, and save it to the tmpData of the first 16 array element  
            for (int j = 0; j < 16; j++) {
                tmpData[j] = byteArrayToInt(newbyte, (pos * 64) + (j * 4));
            }

            //  Summary of the evaluation function  
            encrypt();
        }

        return 20;
    }

    //  Formatted input byte array format  
    private byte[] byteArrayFormatData(byte[] bytedata) {
        //  The number of supplementary 0  
        int zeros = 0;

        //  The total number of digits after the invigorating bit  
        int size = 0;

        //  The original data length  
        int n = bytedata.length;

        //  Die 64 bits of the remaining after  
        int m = n % 64;

        //  The calculation of the number of 0, and to add the length 10 total  
        if (m < 56) {
            zeros = 55 - m;
            size = n - m + 64;
        } else if (m == 56) {
            zeros = 63;
            size = n + 8 + 64;
        } else {
            zeros = 63 - m + 56;
            size = (n + 64) - m + 64;
        }

        //  BU-generated after the contents of the new array  
        byte[] newbyte = new byte[size];
        //  Copy the front of the array  
        System.arraycopy(bytedata, 0, newbyte, 0, n);

        //  Get array Append data element  
        int l = n;
        //  Supplement 1 operation  
        newbyte[l++] = (byte) 0x80;

        //  Complement 0 operations  
        for (int i = 0; i < zeros; i++) {
            newbyte[l++] = (byte) 0x00;
        }

        //  Calculated data length, supplement data length bit 8 bytes, long integer  
        long N = (long) n * 8;
        byte h8 = (byte) (N & 0xFF);
        byte h7 = (byte) ((N >> 8) & 0xFF);
        byte h6 = (byte) ((N >> 16) & 0xFF);
        byte h5 = (byte) ((N >> 24) & 0xFF);
        byte h4 = (byte) ((N >> 32) & 0xFF);
        byte h3 = (byte) ((N >> 40) & 0xFF);
        byte h2 = (byte) ((N >> 48) & 0xFF);
        byte h1 = (byte) (N >> 56);
        newbyte[l++] = h1;
        newbyte[l++] = h2;
        newbyte[l++] = h3;
        newbyte[l++] = h4;
        newbyte[l++] = h5;
        newbyte[l++] = h6;
        newbyte[l++] = h7;
        newbyte[l++] = h8;

        return newbyte;
    }

    private int f1(int x, int y, int z) {
        return (x & y) | (~x & z);
    }

    private int f2(int x, int y, int z) {
        return x ^ y ^ z;
    }

    private int f3(int x, int y, int z) {
        return (x & y) | (x & z) | (y & z);
    }

    private int f4(int x, int y) {
        return (x << y) | x >>> (32 - y);
    }

    //  Unit summary calculation function  
    private void encrypt() {
        for (int i = 16; i <= 79; i++) {
            tmpData[i] = f4(tmpData[i - 3] ^ tmpData[i - 8] ^ tmpData[i - 14] ^
                    tmpData[i - 16], 1);
        }

        int[] tmpabcde = new int[5];

        for (int i1 = 0; i1 < tmpabcde.length; i1++) {
            tmpabcde[i1] = digestInt[i1];
        }

        for (int j = 0; j <= 19; j++) {
            int tmp = f4(tmpabcde[0], 5) +
                f1(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
                tmpData[j] + 0x5a827999;
            tmpabcde[4] = tmpabcde[3];
            tmpabcde[3] = tmpabcde[2];
            tmpabcde[2] = f4(tmpabcde[1], 30);
            tmpabcde[1] = tmpabcde[0];
            tmpabcde[0] = tmp;
        }

        for (int k = 20; k <= 39; k++) {
            int tmp = f4(tmpabcde[0], 5) +
                f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
                tmpData[k] + 0x6ed9eba1;
            tmpabcde[4] = tmpabcde[3];
            tmpabcde[3] = tmpabcde[2];
            tmpabcde[2] = f4(tmpabcde[1], 30);
            tmpabcde[1] = tmpabcde[0];
            tmpabcde[0] = tmp;
        }

        for (int l = 40; l <= 59; l++) {
            int tmp = f4(tmpabcde[0], 5) +
                f3(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
                tmpData[l] + 0x8f1bbcdc;
            tmpabcde[4] = tmpabcde[3];
            tmpabcde[3] = tmpabcde[2];
            tmpabcde[2] = f4(tmpabcde[1], 30);
            tmpabcde[1] = tmpabcde[0];
            tmpabcde[0] = tmp;
        }

        for (int m = 60; m <= 79; m++) {
            int tmp = f4(tmpabcde[0], 5) +
                f2(tmpabcde[1], tmpabcde[2], tmpabcde[3]) + tmpabcde[4] +
                tmpData[m] + 0xca62c1d6;
            tmpabcde[4] = tmpabcde[3];
            tmpabcde[3] = tmpabcde[2];
            tmpabcde[2] = f4(tmpabcde[1], 30);
            tmpabcde[1] = tmpabcde[0];
            tmpabcde[0] = tmp;
        }

        for (int i2 = 0; i2 < tmpabcde.length; i2++) {
            digestInt[i2] = digestInt[i2] + tmpabcde[i2];
        }

        for (int n = 0; n < tmpData.length; n++) {
            tmpData[n] = 0;
        }
    }

    // 4 A byte array to convert to an integer  
    private int byteArrayToInt(byte[] bytedata, int i) {
        return ((bytedata[i] & 0xff) << 24) | ((bytedata[i + 1] & 0xff) << 16) |
        ((bytedata[i + 2] & 0xff) << 8) | (bytedata[i + 3] & 0xff);
    }

    //  Integer is converted to a 4-byte array  
    private void intToByteArray(int intValue, byte[] byteData, int i) {
        byteData[i] = (byte) (intValue >>> 24);
        byteData[i + 1] = (byte) (intValue >>> 16);
        byteData[i + 2] = (byte) (intValue >>> 8);
        byteData[i + 3] = (byte) intValue;
    }

    //  To convert a hexadecimal string bytes  
    private static String byteToHexString(byte ib) {
        char[] Digit = {
                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c',
                'd', 'e', 'f'
            };
        char[] ob = new char[2];
        ob[0] = Digit[(ib >>> 4) & 0X0F];
        ob[1] = Digit[ib & 0X0F];

        String s = new String(ob);

        return s;
    }

    //  Converts an array of bytes into a string of hexadecimal characters  
    private static String byteArrayToHexString(byte[] bytearray) {
        String strDigest = "";

        for (int i = 0; i < bytearray.length; i++) {
            strDigest += byteToHexString(bytearray[i]);
        }

        return strDigest;
    }

    //  Calculates sha  -1 Summary returns the corresponding byte array  
    public byte[] getDigestOfBytes(byte[] byteData) {
        process_input_bytes(byteData);

        byte[] digest = new byte[20];

        for (int i = 0; i < digestInt.length; i++) {
            intToByteArray(digestInt[i], digest, i * 4);
        }

        return digest;
    }

    //  Calculates sha  -1 Summary returns the corresponding hexadecimal string  
    public String getDigestOfString(byte[] byteData) {
        return byteArrayToHexString(getDigestOfBytes(byteData));
    }

    public static void main(String[] args) {
        String data = "1";
        System.out.println(data);

        String digest = new SHA1().getDigestOfString(data.getBytes());
        System.out.println(digest);
    }
}