The crypto/sha256 godoc actually has a snippet that shows how to do that (it’s basically the same code as James): package main import ( “crypto/sha256” “fmt” “io” “log” “os” ) func main() { f, err := os.Open(“file.txt”) if err != nil { log.Fatal(err) } defer f.Close() h := sha256.New() if _, err := io.Copy(h, f); … Read more
Don’t use a simple hash, or even a salted hash. Use some sort of key-strengthening technique like bcrypt (with a .NET implementation here) or PBKDF2 (with a built-in implementation). Here’s an example using PBKDF2. To generate a key from your password… string password = GetPasswordFromUserInput(); // specify that we want to randomly generate a 20-byte … Read more
Switching to SHA512 will hardly make your website more secure. You should not write your own password hashing function. Instead, use an existing implementation. SHA256 and SHA512 are message digests, they were never meant to be password-hashing (or key-derivation) functions. (Although a message digest could be used a building block for a KDF, such as … Read more
Yes, a SHA256 is always 256 bits long, equivalent to 32 bytes, or 64 bytes in an hexadecimal string format. You can even use char(64) instead of varchar(64) since the size won’t change.
There is technically a limit, but it’s quite large. The padding scheme used for SHA-256 requires that the size of the input (in bits) be expressed as a 64-bit number. Therefore, the maximum size is (264-1)/8 bytes ~= 2’091’752 terabytes. That renders the limit almost entirely theoretical, not practical. Most people don’t have the storage … Read more
Could this be a typo? (two Ps in ppasscode, intended?) $_POST[‘ppasscode’]; I would make sure and do: print_r($_POST); and make sure the data is accurate there, and then echo out what it should look like: echo hash(‘sha256’, $_POST[‘ppasscode’]); Compare this output to what you have in the database (manually). By doing this you’re exploring your … Read more
import hmac import hashlib import base64 dig = hmac.new(b’1234567890′, msg=your_bytes_string, digestmod=hashlib.sha256).digest() base64.b64encode(dig).decode() # py3k-mode ‘Nace+U3Az4OhN7tISqgs1vdLBHBEijWcBeCqL5xN9xg=’
This is what I’m using for SHA1: #import <CommonCrypto/CommonDigest.h> + (NSData *)sha1:(NSData *)data { unsigned char hash[CC_SHA1_DIGEST_LENGTH]; if ( CC_SHA1([data bytes], [data length], hash) ) { NSData *sha1 = [NSData dataWithBytes:hash length:CC_SHA1_DIGEST_LENGTH]; return sha1; } return nil; } Replace CC_SHA1 with CC_SHA256 (or whichever you need), as well as CC_SHA1_DIGEST_LENGTH with CC_SHA256_DIGEST_LENGTH.
The implementation could be like that public static String sha256_hash(String value) { StringBuilder Sb = new StringBuilder(); using (SHA256 hash = SHA256Managed.Create()) { Encoding enc = Encoding.UTF8; Byte[] result = hash.ComputeHash(enc.GetBytes(value)); foreach (Byte b in result) Sb.Append(b.ToString(“x2”)); } return Sb.ToString(); } Edit: Linq implementation is more concise, but, probably, less readable: public static String sha256_hash(String … Read more
Here’s how I did it: void sha256_hash_string (unsigned char hash[SHA256_DIGEST_LENGTH], char outputBuffer[65]) { int i = 0; for(i = 0; i < SHA256_DIGEST_LENGTH; i++) { sprintf(outputBuffer + (i * 2), “%02x”, hash[i]); } outputBuffer[64] = 0; } void sha256_string(char *string, char outputBuffer[65]) { unsigned char hash[SHA256_DIGEST_LENGTH]; SHA256_CTX sha256; SHA256_Init(&sha256); SHA256_Update(&sha256, string, strlen(string)); SHA256_Final(hash, &sha256); int … Read more