我找到了 EVP_BytesToKey
方法的伪代码说明（在openssl源代码的/doc/ssleay.txt中）：
M[0]=MD(data . salt);for (i=1; i<count; i++) M[0]=MD(M[0]);i=1while (data still needed for key and iv) { M[i]=MD(M[i-1] . data . salt); for (i=1; i<count; i++) M[i]=MD(M[i]); i++; }If the salt is NULL, it is not used.The digests are concatenated together.M = M[0] . M[1] . M[2] .......因此，基于此，我能够提出这种C＃方法（该方法似乎可以满足我的目的，并假定使用32字节的密钥和16字节的iv）：
private static void DeriveKeyAndIV(byte[] data, byte[] salt, int count, out byte[] key, out byte[] iv){ List<byte> hashList = new List<byte>(); byte[] currentHash = new byte[0]; int preHashLength = data.Length + ((salt != null) ? salt.Length : 0); byte[] preHash = new byte[preHashLength]; System.Buffer.BlockCopy(data, 0, preHash, 0, data.Length); if (salt != null) System.Buffer.BlockCopy(salt, 0, preHash, data.Length, salt.Length); MD5 hash = MD5.Create(); currentHash = hash.ComputeHash(preHash); for (int i = 1; i < count; i++) { currentHash = hash.ComputeHash(currentHash); } hashList.AddRange(currentHash); while (hashList.Count < 48) // for 32-byte key and 16-byte iv { preHashLength = currentHash.Length + data.Length + ((salt != null) ? salt.Length : 0); preHash = new byte[preHashLength]; System.Buffer.BlockCopy(currentHash, 0, preHash, 0, currentHash.Length); System.Buffer.BlockCopy(data, 0, preHash, currentHash.Length, data.Length); if (salt != null) System.Buffer.BlockCopy(salt, 0, preHash, currentHash.Length + data.Length, salt.Length); currentHash = hash.ComputeHash(preHash); for (int i = 1; i < count; i++) { currentHash = hash.ComputeHash(currentHash); } hashList.AddRange(currentHash); } hash.Clear(); key = new byte[32]; iv = new byte[16]; hashList.CopyTo(0, key, 0, 32); hashList.CopyTo(32, iv, 0, 16);}更新 ：这里更多/更少相同的实现，但是使用.NET
DeriveBytes接口：https
://gist.github.com/1339719
OpenSSL
1.1.0c更改了某些内部组件中使用的摘要算法。以前使用MD5，并且1.1.0切换到SHA256。小心的变化不影响你在这两个
EVP_BytesToKey和命令状
opensslenc。
