crypto: add a crypto.pbkdf2 module

vlib/crypto/pbkdf2/pbkdf2.v

@@ -0,0 +1,58 @@
+// Based off: https://golang.org/x/crypto/pbkdf2
+module pbkdf2
+
+import crypto.hmac
+import crypto.sha256
+import crypto.sha512
+import hash
+
+// key derives a key from the password, salt and iteration count
+// example pbkdf2.key('test'.bytes(), '123456'.bytes(), 1000, 64, sha512.new())
+pub fn key(password []u8, salt []u8, count int, key_length int, h hash.Hash) ![]u8 {
+	mut fun := fn (b []u8) []u8 {
+		return []u8{}
+	}
+	mut block_size := 0
+	mut size := 0
+	match h {
+		sha256.Digest {
+			fun = sha256.sum256
+			block_size = sha256.block_size
+			size = sha256.size
+		}
+		sha512.Digest {
+			fun = sha512.sum512
+			block_size = sha512.block_size
+			size = sha512.size
+		}
+		else {
+			panic('Unsupported hash')
+		}
+	}
+
+	hash_length := size
+	block_count := (key_length + hash_length - 1) / hash_length
+	mut output := []u8{}
+	mut last := []u8{}
+	mut buf := []u8{len: 4}
+	for i := 1; i <= block_count; i++ {
+		last << salt
+
+		buf[0] = u8(i >> 24)
+		buf[1] = u8(i >> 16)
+		buf[2] = u8(i >> 8)
+		buf[3] = u8(i)
+
+		last << buf
+		mut xorsum := hmac.new(password, last, fun, block_size)
+		mut last_hash := xorsum.clone()
+		for j := 1; j < count; j++ {
+			last_hash = hmac.new(password, last_hash, fun, block_size)
+			for k in 0 .. xorsum.len {
+				xorsum[k] ^= last_hash[k]
+			}
+		}
+		output << xorsum
+	}
+	return output[..key_length]
+}

vlib/crypto/pbkdf2/pbkdf2_test.v

@@ -0,0 +1,18 @@
+import crypto.sha512
+import crypto.sha256
+import crypto.pbkdf2
+
+const data = 'test'
+const password = '123456'
+
+fn test_sha512() {
+	// vfmt off
+	assert pbkdf2.key(data.bytes(), password.bytes(), 1000, 64, sha512.new())! == [u8(149) 155 168 16 77 243 26 192 128 222 29 139 38 173 131 82 73 152 197 253 66 64 11 103 32 110 95 116 143 4 104 70 176 24 99 48 224 77 47 184 193 59 98 191 18 172 4 119 83 93 198 101 118 131 223 150 215 172 170 166 205 187 247 160]
+	// vfmt on
+}
+
+fn test_sha256() {
+	// vfmt off
+	assert pbkdf2.key(data.bytes(), password.bytes(), 1000, 32, sha256.new())! == [u8(110) 95 68 212 254 34 114 21 43 19 155 141 36 158 236 51 16 244 85 107 245 172 219 25 128 109 111 18 25 14 9 149]
+	// vfmt on
+}