问题
In Objective C I\'ve been using the following code to hash a string:
-(NSString *) sha1:(NSString*)stringToHash {
const char *cStr = [stringToHash UTF8String];
unsigned char result[20];
CC_SHA1( cStr, strlen(cStr), result );
return [NSString stringWithFormat:@\"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X\",
result[0], result[1], result[2], result[3],
result[4], result[5], result[6], result[7],
result[8], result[9], result[10], result[11],
result[12], result[13], result[14], result[15],
result[16], result[17], result[18], result[19]
];
}
Now I need the same for Android but can\'t find out how to do it. I\'ve been looking for example at this: Make SHA1 encryption on Android? but that doesn\'t give me the same result as on iPhone. Can anyone point me in the right direction?
回答1:
You don't need andorid for this. You can just do it in simple java.
Have you tried a simple java example and see if this returns the right sha1.
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
public class AeSimpleSHA1 {
private static String convertToHex(byte[] data) {
StringBuilder buf = new StringBuilder();
for (byte b : data) {
int halfbyte = (b >>> 4) & 0x0F;
int two_halfs = 0;
do {
buf.append((0 <= halfbyte) && (halfbyte <= 9) ? (char) ('0' + halfbyte) : (char) ('a' + (halfbyte - 10)));
halfbyte = b & 0x0F;
} while (two_halfs++ < 1);
}
return buf.toString();
}
public static String SHA1(String text) throws NoSuchAlgorithmException, UnsupportedEncodingException {
MessageDigest md = MessageDigest.getInstance("SHA-1");
byte[] textBytes = text.getBytes("iso-8859-1");
md.update(textBytes, 0, textBytes.length);
byte[] sha1hash = md.digest();
return convertToHex(sha1hash);
}
}
Also share what your expected sha1 should be. Maybe ObjectC is doing it wrong.
回答2:
A simpler SHA-1 method: (updated from the commenter's suggestions, also using a massively more efficient byte->string algorithm)
String sha1Hash( String toHash )
{
String hash = null;
try
{
MessageDigest digest = MessageDigest.getInstance( "SHA-1" );
byte[] bytes = toHash.getBytes("UTF-8");
digest.update(bytes, 0, bytes.length);
bytes = digest.digest();
// This is ~55x faster than looping and String.formating()
hash = bytesToHex( bytes );
}
catch( NoSuchAlgorithmException e )
{
e.printStackTrace();
}
catch( UnsupportedEncodingException e )
{
e.printStackTrace();
}
return hash;
}
// http://stackoverflow.com/questions/9655181/convert-from-byte-array-to-hex-string-in-java
final protected static char[] hexArray = "0123456789ABCDEF".toCharArray();
public static String bytesToHex( byte[] bytes )
{
char[] hexChars = new char[ bytes.length * 2 ];
for( int j = 0; j < bytes.length; j++ )
{
int v = bytes[ j ] & 0xFF;
hexChars[ j * 2 ] = hexArray[ v >>> 4 ];
hexChars[ j * 2 + 1 ] = hexArray[ v & 0x0F ];
}
return new String( hexChars );
}
回答3:
If you can get away with using Guava it is by far the simplest way to do it, and you don't have to reinvent the wheel:
final HashCode hashCode = Hashing.sha1().hashString(yourValue, Charset.defaultCharset());
You can then take the hashed value and get it as a byte[], as an int, or as a long.
No wrapping in a try catch, no shenanigans. And if you decide you want to use something other than SHA-1, Guava also supports sha256, sha 512, and a few I had never even heard about like adler32 and murmur3.
回答4:
final MessageDigest digest = MessageDigest.getInstance("SHA-1");
result = digest.digest(stringToHash.getBytes("UTF-8"));
// Another way to construct HEX, my previous post was only the method like your solution
StringBuilder sb = new StringBuilder();
for (byte b : result) // This is your byte[] result..
{
sb.append(String.format("%02X", b));
}
String messageDigest = sb.toString();
回答5:
Totally based on @Whymarrh's answer, this is my implementation, tested and working fine, no dependencies:
public static String getSha1Hex(String clearString)
{
try
{
MessageDigest messageDigest = MessageDigest.getInstance("SHA-1");
messageDigest.update(clearString.getBytes("UTF-8"));
byte[] bytes = messageDigest.digest();
StringBuilder buffer = new StringBuilder();
for (byte b : bytes)
{
buffer.append(Integer.toString((b & 0xff) + 0x100, 16).substring(1));
}
return buffer.toString();
}
catch (Exception ignored)
{
ignored.printStackTrace();
return null;
}
}
回答6:
Android comes with Apache's Commons Codec - or you add it as dependency. Then do:
String myHexHash = DigestUtils.shaHex(myFancyInput);
That is the old deprecated method you get with Android 4 by default. The new versions of DigestUtils bring all flavors of shaHex() methods like sha256Hex() and also overload the methods with different argument types.
http://commons.apache.org/proper/commons-codec//javadocs/api-release/org/apache/commons/codec/digest/DigestUtils.html
回答7:
The method you are looking for is not specific to Android, but to Java in general. You're looking for the MessageDigest (import java.security.MessageDigest).
An implementation of a sha512(String s) method can be seen here, and the change for a SHA-1 hash would be changing line 71 to:
MessageDigest md = MessageDigest.getInstance("SHA-1");
回答8:
String.format("%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X", result[0], result[1], result[2], result[3],
result[4], result[5], result[6], result[7],
result[8], result[9], result[10], result[11],
result[12], result[13], result[14], result[15],
result[16], result[17], result[18], result[19]);
来源：https://stackoverflow.com/questions/5980658/how-to-sha1-hash-a-string-in-android