如何将使用下面方法加密后的字符串转换回原始字符串? public String computeDigest(String msg){
try {
java.security.MessageDigest alg = java.security.MessageDigest.getInstance("SHA-1");
alg.reset();
alg.update(msg.getBytes());
byte[] hash = alg.digest();
String digest = "";
for (int i = 0;i < hash.length;i++){
int v = hash[i] & 0xFF;
if( v < 16 ) digest += "0";
digest += Integer.toString(v,16).toUpperCase();
}
return digest;
}catch (Exception e) {
return msg;
}
}
try {
java.security.MessageDigest alg = java.security.MessageDigest.getInstance("SHA-1");
alg.reset();
alg.update(msg.getBytes());
byte[] hash = alg.digest();
String digest = "";
for (int i = 0;i < hash.length;i++){
int v = hash[i] & 0xFF;
if( v < 16 ) digest += "0";
digest += Integer.toString(v,16).toUpperCase();
}
return digest;
}catch (Exception e) {
return msg;
}
}
没有办法拿到原文,否则
单向算法也可以啊
加密之后再与数据库中已经加过密的比较不是一样吗