diff --git a/ieee754.py b/ieee754.py
new file mode 100644
index 0000000..5a8bb5f
--- /dev/null
+++ b/ieee754.py
@@ -0,0 +1,54 @@
+def bin2hex(s):
+    ht = [ str(i) for i in range(10) ] + [ "A","B","C","D","E","F" ]
+    h = ""
+    while s != "":
+        h = ht[int(s[-4:],2)] + h
+        s = s[:-4]
+    return "0x"+h
+
+def to_mantisse(d,n=23):
+    s = ""
+    for i in range(n):
+        d *= 2
+        s += str(int(d)%2)
+    return s
+
+def to_binary(d,n=8):
+    s = ""
+    for i in range(n):
+        s = str(d & 1) + s
+        d = d >> 1
+    return s
+
+def to_ieee754(d,el,ml):
+    if d < 0:
+        s = 1
+        d *= -1
+    else:
+        s = 0
+    g = 0
+    while d >= 2:
+        d /= 2
+        g += 1
+    while d <= 0.5:
+        d *= 2
+        g -= 1
+    bias = 2**(el-1)-1
+    e = g+bias
+    return str(s)+to_binary(e,n=el)+to_mantisse(d,n=ml)
+
+def to_ieee754_single(d):
+    return to_ieee754(d,el=8,ml=23)
+
+def to_ieee754_double(d):
+    return to_ieee754(d,el=11,ml=52)
+
+def to_ieee754_single_hex(d):
+    return bin2hex(to_ieee754_single(d))
+
+def to_ieee754_double_hex(d):
+    return bin2hex(to_ieee754_double(d))
+
+if __name__ == "__main__":
+    print(bin2hex(to_ieee754_double(-2.5)))
+    print(bin2hex(to_ieee754_double(-1.75)))
diff --git a/rsa.py b/rsa.py
new file mode 100644
index 0000000..000a8eb
--- /dev/null
+++ b/rsa.py
@@ -0,0 +1,16 @@
+def e(m,e,n):
+    f = 1
+    print("%d ^ %d mod %d" %(m,e,n))
+    while e != 1:
+        print("= %d ^ %d * %d mod %d" % (m,e,f,n))
+        if e % 2 == 1:
+            f *= m
+            e -= 1
+            f = f % n
+        m = (m * m) % n
+        e /= 2
+    print("= %d * %d mod %d" % (m,f,n))
+    c = (m*f) % n
+    print("= %d" % c)
+
+e(20,13,33)