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SHA1Digest.javaAPI DocAndroid 1.5 API7000Wed May 06 22:41:06 BST 2009org.bouncycastle.crypto.digests

SHA1Digest

public class SHA1Digest extends GeneralDigest
implementation of SHA-1 as outlined in "Handbook of Applied Cryptography", pages 346 - 349. It is interesting to ponder why the, apart from the extra IV, the other difference here from MD5 is the "endienness" of the word processing!

Fields Summary
private static final int
DIGEST_LENGTH
private int
H1
private int
H2
private int
H3
private int
H4
private int
H5
private int[]
X
private int
xOff
private static final int
Y1
private static final int
Y2
private static final int
Y3
private static final int
Y4
Constructors Summary
public SHA1Digest()
Standard constructor


           
     
    
        reset();
    
public SHA1Digest(SHA1Digest t)
Copy constructor. This will copy the state of the provided message digest.

        super(t);

        H1 = t.H1;
        H2 = t.H2;
        H3 = t.H3;
        H4 = t.H4;
        H5 = t.H5;

        System.arraycopy(t.X, 0, X, 0, t.X.length);
        xOff = t.xOff;
    
Methods Summary
public intdoFinal(byte[] out, int outOff)

        finish();

        unpackWord(H1, out, outOff);
        unpackWord(H2, out, outOff + 4);
        unpackWord(H3, out, outOff + 8);
        unpackWord(H4, out, outOff + 12);
        unpackWord(H5, out, outOff + 16);

        reset();

        return DIGEST_LENGTH;
    
private intf(int u, int v, int w)

   
      
            
            
            
    
        return ((u & v) | ((~u) & w));
    
private intg(int u, int v, int w)

        return ((u & v) | (u & w) | (v & w));
    
public java.lang.StringgetAlgorithmName()

        return "SHA-1";
    
public intgetDigestSize()

        return DIGEST_LENGTH;
    
private inth(int u, int v, int w)

        return (u ^ v ^ w);
    
protected voidprocessBlock()

        //
        // expand 16 word block into 80 word block.
        //
        for (int i = 16; i < 80; i++)
        {
            int t = X[i - 3] ^ X[i - 8] ^ X[i - 14] ^ X[i - 16];
            X[i] = t << 1 | t >>> 31;
        }

        //
        // set up working variables.
        //
        int     A = H1;
        int     B = H2;
        int     C = H3;
        int     D = H4;
        int     E = H5;

        //
        // round 1
        //
        int idx = 0;
        
        for (int j = 0; j < 4; j++)
        {
            // E = rotateLeft(A, 5) + f(B, C, D) + E + X[idx++] + Y1
            // B = rotateLeft(B, 30)
            E += (A << 5 | A >>> 27) + f(B, C, D) + X[idx++] + Y1;
            B = B << 30 | B >>> 2;
        
            D += (E << 5 | E >>> 27) + f(A, B, C) + X[idx++] + Y1;
            A = A << 30 | A >>> 2;
       
            C += (D << 5 | D >>> 27) + f(E, A, B) + X[idx++] + Y1;
            E = E << 30 | E >>> 2;
       
            B += (C << 5 | C >>> 27) + f(D, E, A) + X[idx++] + Y1;
            D = D << 30 | D >>> 2;

            A += (B << 5 | B >>> 27) + f(C, D, E) + X[idx++] + Y1;
            C = C << 30 | C >>> 2;
        }
        
        //
        // round 2
        //
        for (int j = 0; j < 4; j++)
        {
            // E = rotateLeft(A, 5) + h(B, C, D) + E + X[idx++] + Y2
            // B = rotateLeft(B, 30)
            E += (A << 5 | A >>> 27) + h(B, C, D) + X[idx++] + Y2;
            B = B << 30 | B >>> 2;   
            
            D += (E << 5 | E >>> 27) + h(A, B, C) + X[idx++] + Y2;
            A = A << 30 | A >>> 2;
            
            C += (D << 5 | D >>> 27) + h(E, A, B) + X[idx++] + Y2;
            E = E << 30 | E >>> 2;
            
            B += (C << 5 | C >>> 27) + h(D, E, A) + X[idx++] + Y2;
            D = D << 30 | D >>> 2;

            A += (B << 5 | B >>> 27) + h(C, D, E) + X[idx++] + Y2;
            C = C << 30 | C >>> 2;
        }
        
        //
        // round 3
        //
        for (int j = 0; j < 4; j++)
        {
            // E = rotateLeft(A, 5) + g(B, C, D) + E + X[idx++] + Y3
            // B = rotateLeft(B, 30)
            E += (A << 5 | A >>> 27) + g(B, C, D) + X[idx++] + Y3;
            B = B << 30 | B >>> 2;
            
            D += (E << 5 | E >>> 27) + g(A, B, C) + X[idx++] + Y3;
            A = A << 30 | A >>> 2;
            
            C += (D << 5 | D >>> 27) + g(E, A, B) + X[idx++] + Y3;
            E = E << 30 | E >>> 2;
            
            B += (C << 5 | C >>> 27) + g(D, E, A) + X[idx++] + Y3;
            D = D << 30 | D >>> 2;

            A += (B << 5 | B >>> 27) + g(C, D, E) + X[idx++] + Y3;
            C = C << 30 | C >>> 2;
        }

        //
        // round 4
        //
        for (int j = 0; j <= 3; j++)
        {
            // E = rotateLeft(A, 5) + h(B, C, D) + E + X[idx++] + Y4
            // B = rotateLeft(B, 30)
            E += (A << 5 | A >>> 27) + h(B, C, D) + X[idx++] + Y4;
            B = B << 30 | B >>> 2;
            
            D += (E << 5 | E >>> 27) + h(A, B, C) + X[idx++] + Y4;
            A = A << 30 | A >>> 2;
            
            C += (D << 5 | D >>> 27) + h(E, A, B) + X[idx++] + Y4;
            E = E << 30 | E >>> 2;
            
            B += (C << 5 | C >>> 27) + h(D, E, A) + X[idx++] + Y4;
            D = D << 30 | D >>> 2;

            A += (B << 5 | B >>> 27) + h(C, D, E) + X[idx++] + Y4;
            C = C << 30 | C >>> 2;
        }


        H1 += A;
        H2 += B;
        H3 += C;
        H4 += D;
        H5 += E;

        //
        // reset start of the buffer.
        //
        xOff = 0;
        for (int i = 0; i < 16; i++)
        {
            X[i] = 0;
        }
    
protected voidprocessLength(long bitLength)

        if (xOff > 14)
        {
            processBlock();
        }

        X[14] = (int)(bitLength >>> 32);
        X[15] = (int)(bitLength & 0xffffffff);
    
protected voidprocessWord(byte[] in, int inOff)

        X[xOff++] = (in[inOff] & 0xff) << 24 | (in[inOff + 1] & 0xff) << 16
                    | (in[inOff + 2] & 0xff) << 8 | in[inOff + 3] & 0xff; 

        if (xOff == 16)
        {
            processBlock();
        }        
    
public voidreset()
reset the chaining variables

        super.reset();

        H1 = 0x67452301;
        H2 = 0xefcdab89;
        H3 = 0x98badcfe;
        H4 = 0x10325476;
        H5 = 0xc3d2e1f0;

        xOff = 0;
        for (int i = 0; i != X.length; i++)
        {
            X[i] = 0;
        }
    
private voidunpackWord(int word, byte[] out, int outOff)

        out[outOff++] = (byte)(word >>> 24);
        out[outOff++] = (byte)(word >>> 16);
        out[outOff++] = (byte)(word >>> 8);
        out[outOff++] = (byte)word;