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Cryptography Jobs

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Fixed-Price - Est. Budget: $ 100 Posted
The work is to build a real time web server that processes transactions on triple-signed contracts between untrusted clients. The communication flow is: 1. The client Alice creates a contract that authorizes a balance operation on a linked account. Example: Contract#704 Amount: 50 To: Bob Signed: Alice 2. The server Notary authenticates it with an encrypted token. Example: Contract#7046035941 Signed: Notary 3. The client Bob claims it and the server processes the transaction. Example: Contract#7046035941 Signed: Bob
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.
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...