+
+
+def ohdave_rsa_encrypt(data, exponent, modulus):
+ '''
+ Implement OHDave's RSA algorithm. See http://www.ohdave.com/rsa/
+
+ Input:
+ data: data to encrypt, bytes-like object
+ exponent, modulus: parameter e and N of RSA algorithm, both integer
+ Output: hex string of encrypted data
+
+ Limitation: supports one block encryption only
+ '''
+
+ payload = int(binascii.hexlify(data[::-1]), 16)
+ encrypted = pow(payload, exponent, modulus)
+ return '%x' % encrypted
+
+
+def base_n(num, n, table):
+ if num == 0:
+ return '0'
+ ret = ''
+ while num:
+ ret = table[num % n] + ret
+ num = num // n
+ return ret
+
+
+def base62(num):
+ return base_n(num, 62, '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ')