Making RSA encryption compatible in Python (PyCrypto) and PHP (OpenSSL)
<p>I am migrating an entire PHP API, and while I used PyCrypto before, I am not sure how to translate the following encryption call, since I need the exact same result. The PHP call is:</p>

<pre><code>define('KEY', "-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC81t5iu5C0JxYq5/XNPiD5ol3Z
w8rw3LtFIUm7y3m8o8wv5qVnzGh6XwQ8LWypdkbBDKWZZrAUd3lybZOP7/82Nb1/
noYj8ixVRdbnYtbsSAbu9PxjB7a/7LCGKsugLkou74PJDadQweM88kzQOx/kzAyV
bS9gCCVUguHcq2vRRQIDAQAB
-----END PUBLIC KEY-----");
$cypher = "";
$result = openssl_public_encrypt($plain, $cypher, KEY, OPENSSL_PKCS1_PADDING);
echo bin2hex($cypher);
</code></pre>

<p>Assuming everything goes right, this prints the content from <code>$cypher</code>, passed to hexadecimal. For a sample input <code>"azzzzzzzzzzzzdfdf"</code> I get something like: <code>"2281aeebc1166cdfb2f17a0a0775d927ca5a9ad999bae0e4954f58bd8082fdf7efe1fd284876530341f714456d7eb8cd44c57b20ab27029b84d5dc77a674bede3fe9065282931404286082e9df8607bdcff0818b90324dfee7d76b566d0f99bebc5cc913372c276ba373712128f1bcc226b59367cff93f7cdd6dbde25b366863"</code>.</p>

<p>I must assume this value as right, since the code was taken from an existing API I am migrating. However, trying the same with <code>PyCrypto</code> (yes, I am migrating the API to be available in Python), I use the following code:</p>

<pre><code>def bin2hex(s):
    return "".join([hex(ord(c))[2:].zfill(2) for c in s])

KEY = """-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC81t5iu5C0JxYq5/XNPiD5ol3Z
w8rw3LtFIUm7y3m8o8wv5qVnzGh6XwQ8LWypdkbBDKWZZrAUd3lybZOP7/82Nb1/
noYj8ixVRdbnYtbsSAbu9PxjB7a/7LCGKsugLkou74PJDadQweM88kzQOx/kzAyV
bS9gCCVUguHcq2vRRQIDAQAB
-----END PUBLIC KEY-----"""

from Crypto.Cipher import PKCS1_v1_5
from Crypto.PublicKey import RSA
encrypter = PKCS1_v1_5.new(RSA.importKey(KEY))
print bin2hex(encrypter.encrypt("azzzzzzzzzzzzdfdf"));
</code></pre>

<p>While I expect the same value be returned and printed, the value finally is <code>"3dd94ffabd01bb0e94010c0fedbcd4eb648f12e5d9e6d934b77ae86f76681d8a1b790cad9fddf6e6720415b4d645e525c33c402fa9778739b8e461790387e9508f7158a5fdc5723f5fc26d166b11a00759f0e0ee3ba6719a2e7c6b918f66e1311d1fff878ee2ca8762e1d6120f1e9585a76cdc7719ca20129ae76182b4277170"</code>.</p>

<p>Using <code>PKCS1_OAEP</code> outputs <code>"290f60f37088c2cb46ae9221b01ff46a463f270ef7cf70bbea49de0b5ae43aec34a0eb46e694cf22f689eb77e808c590fdc30eda09f9d3f3cb8c15e0505bf5a984c2a121bc9fa83c6b5ccf50235f072467b4ae9cdf0f0ee2e486626ffa62ad1aa715fbe29e8afe4ceab3ca5a5df4c1dc75d7f258285d7ff1f4f2b4dcb7a8413a"</code>.</p>

<p>It is easy to tell that I must fix my python code. How can I fix my python code so it returns the exact same result as the given PHP call?</p>