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Cryptography Jobs

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Hourly - Est. Time: Less than 1 week, 10-30 hrs/week - Posted
I'm looking for someone who is an expert in bouncycastle security APIs to help me debug some code. It works 99% of the time. But once in a while I get an exception (org.bouncycastle.crypto.DataLengthException: last block incomplete in decryption) Once I find the right person to figure this out, I will provide data to replicate the problem. A code where the problem exists is below: public static DBObject decodePayload(String initVector, String profilePayload) throws DecoderException, InvalidCipherTextException { byte[] secret = Hex.decodeHex(PAYLOAD_SECRET_STRING.toCharArray()); byte[] iv = Base64.decodeBase64(initVector); byte[] encData = Base64.decodeBase64(profilePayload); KeyParameter keyParam = new KeyParameter(secret); CipherParameters params = new ParametersWithIV(keyParam, iv); BlockCipherPadding padding = new PKCS7Padding(); BufferedBlockCipher cipher = new PaddedBufferedBlockCipher(new CBCBlockCipher(new AESEngine()), padding); cipher.reset(); cipher.init(false,...
Fixed-Price - Est. Budget: $ 200 Posted
Using Arbitrary Messaging Serialize a Newtonsoft JSON object, transmit via NXTLib encrypted message. At the receiving address accept the message and reconstitute Newtonsoft JSON object.
Hourly - Est. Time: Less than 1 week, 10-30 hrs/week - Posted
Scope: An embedded system needs a software encryption for data in motion between MCUs via various data lines. Goal: To develop an encryption routine that will become an integral part of the C++ code for the embedded system. First, to review algorithms suitable for the embedded system and select one that is mathematically simple and robust to keep the burden on the MCUs light. General: The encryption is to be used between the embedded systems that are non-public, i.e., standalone. However, the system may eventually have port(s) for internet connection. Deliverables: Source code and a written report to describes the details of the math and how to implement the encryption routine into the main code. Vetting: A short video interview may be necessary. Please propose the charge rate and the time length of the project but the details may be discussed further in the interview. ** I am sorry to be blunt--"This is not a "let's try and figure out and see if it works" hobby research...
Fixed-Price - Est. Budget: $ 7,000 Posted
We need library in restricted C dialect, implementing high-level elliptic curve cryptographic primitives. We need elliptic curves because of short keys. Overall, we need a 48-byte digital signature. • Library should support brainpoolP192r1 or brainpoolP192t1. Other curves are acceptable if 192-bit. We are not interested in non-192-bit curves. • Library should generate public and private key based on truly random data. • Library should sign data with private key in under 100ms. • Library should verify signature with public key in under 100ms. • Not be vulnerable to crypto attacks. • Library should be written without dynamic memory allocation. No malloc/calloc/realloc/free, just global variables and stack. • Library should be written without libc. • Library should be optimized for STM32F205. • Library should targeted at GCC 4.6.0 • Library should be well commented. • Library should be styled according to Linux kernel code style. • Library should be split to files. • Library...
Hourly - Est. Time: Less than 1 week, 10-30 hrs/week - Posted
I need a particular Android application to be reverse engineered / Debugged. The general idea is that there are various HTTP(s) calls made by the app, however the POSTdata is encrypted and i need somebody who will be able to find the encryption method/signing key. There is opportunity for alot of work if you are good at this.