add utils.py

diff --git a/app/model/utils.py b/app/model/utils.py
new file mode 100644 (file)
index 0000000..ece9287
--- /dev/null
+++ b/app/model/utils.py
@@ -0,0 +1,65 @@
+import six
+import hmac
+import hashlib
+import sha3
+from binascii import hexlify
+from binascii import unhexlify
+from app.model.edwards25519 import *
+# from bytom.signatures import ed25519
+
+if six.PY3:
+    def byte2int(b):
+        return b
+    def int2byte(i):
+        return bytes(chr(i % 256), encoding="UTF-8")
+
+elif six.PY2:
+    def byte2int(b):
+        return ord(b)
+    def int2byte(i):
+        return chr(i % 256)
+
+L = 2 ** 252 + 27742317777372353535851937790883648493
+
+def sha3_digest_256(data):
+    s = sha3.sha3_256()
+    s.update(data)
+    return s.digest()
+
+def hmac_sha_512(data, key):
+    digest = hmac.new(key, msg=data, digestmod=hashlib.sha512).digest()
+    return digest
+
+def sha_512(data):
+    md = hashlib.sha512()
+    md.update(data)
+    return md.digest()
+
+def hex2int(hex):
+    ## converts a hex string to integer
+    unhex = unhexlify(hex)
+    s = 0
+    for i in range(len(unhex)):
+        s += 256 ** i * byte2int(unhex[i])
+    return s
+
+def int2hex(int):
+    ## converts an integer to a little endian encoded hex string
+    return hexlify(encodeint(int))
+
+def sc_reduce32(input):
+    ## convert hex string input to integer
+    int = hex2int(input)
+    ## reduce mod l
+    modulo = int % L
+    ## convert back to hex string for return value
+    return int2hex(modulo)
+
+def sc_muladd(a, b, c):
+    a_int = hex2int(a)
+    b_int = hex2int(b)
+    c_int = hex2int(c)
+    
+    s = a_int * b_int + c_int
+    modulo = s % L
+    return int2hex(modulo)