CryptoKey.cpp

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// CryptoKey.cpp
 
// Implements the cCryptoKey class representing a RSA public key in mbedTLS
 
#include "Globals.h"
#include "CryptoKey.h"
 
 
 
 
 
cCryptoKey::cCryptoKey(void)
{
    mbedtls_pk_init(&m_Pk);
    m_CtrDrbg.Initialize("rsa_pubkey", 10);
}
 
 
 
 
 
cCryptoKey::cCryptoKey(const AString & a_PublicKeyData)
{
    mbedtls_pk_init(&m_Pk);
    m_CtrDrbg.Initialize("rsa_pubkey", 10);
    int res = ParsePublic(a_PublicKeyData.data(), a_PublicKeyData.size());
    if (res != 0)
    {
        LOGWARNING("Failed to parse public key: -0x%x", res);
        ASSERT(!"Cannot parse PubKey");
        return;
    }
}
 
 
 
 
 
cCryptoKey::cCryptoKey(const AString & a_PrivateKeyData, const AString & a_Password)
{
    mbedtls_pk_init(&m_Pk);
    m_CtrDrbg.Initialize("rsa_privkey", 11);
    int res = ParsePrivate(a_PrivateKeyData.data(), a_PrivateKeyData.size(), a_Password);
    if (res != 0)
    {
        LOGWARNING("Failed to parse private key: -0x%x", res);
        ASSERT(!"Cannot parse PrivKey");
        return;
    }
}
 
 
 
 
 
cCryptoKey::~cCryptoKey()
{
    mbedtls_pk_free(&m_Pk);
}
 
 
 
 
 
int cCryptoKey::Decrypt(const Byte * a_EncryptedData, size_t a_EncryptedLength, Byte * a_DecryptedData, size_t a_DecryptedMaxLength)
{
    ASSERT(IsValid());
 
    size_t DecryptedLen = a_DecryptedMaxLength;
    int res = mbedtls_pk_decrypt(&m_Pk,
        a_EncryptedData, a_EncryptedLength,
        a_DecryptedData, &DecryptedLen, a_DecryptedMaxLength,
        mbedtls_ctr_drbg_random, m_CtrDrbg.GetInternal()
    );
    if (res != 0)
    {
        return res;
    }
    return static_cast<int>(DecryptedLen);
}
 
 
 
 
 
int cCryptoKey::Encrypt(const Byte * a_PlainData, size_t a_PlainLength, Byte * a_EncryptedData, size_t a_EncryptedMaxLength)
{
    ASSERT(IsValid());
 
    size_t EncryptedLength = a_EncryptedMaxLength;
    int res = mbedtls_pk_encrypt(&m_Pk,
        a_PlainData, a_PlainLength, a_EncryptedData, &EncryptedLength, a_EncryptedMaxLength,
        mbedtls_ctr_drbg_random, m_CtrDrbg.GetInternal()
    );
    if (res != 0)
    {
        return res;
    }
    return static_cast<int>(EncryptedLength);
}
 
 
 
 
 
int cCryptoKey::ParsePublic(const void * a_Data, size_t a_NumBytes)
{
    ASSERT(!IsValid());  // Cannot parse a second key
 
    return mbedtls_pk_parse_public_key(&m_Pk, static_cast<const unsigned char *>(a_Data), a_NumBytes);
}
 
 
 
 
 
int cCryptoKey::ParsePrivate(const void * a_Data, size_t a_NumBytes, const AString & a_Password)
{
    ASSERT(!IsValid());  // Cannot parse a second key
    // mbedTLS requires that PEM-encoded data is passed including the terminating NUL byte,
    // and DER-encoded data is decoded properly even with an extra trailing NUL byte, so we simply add one to everything:
    AString keyData(static_cast<const char *>(a_Data), a_NumBytes);
 
    if (a_Password.empty())
    {
        return mbedtls_pk_parse_key(&m_Pk, reinterpret_cast<const unsigned char *>(keyData.data()), a_NumBytes + 1, nullptr, 0, mbedtls_ctr_drbg_random, m_CtrDrbg.GetInternal());
    }
    else
    {
        return mbedtls_pk_parse_key(
            &m_Pk,
            reinterpret_cast<const unsigned char *>(keyData.data()), a_NumBytes + 1,
            reinterpret_cast<const unsigned char *>(a_Password.c_str()), a_Password.size(),
            mbedtls_ctr_drbg_random, m_CtrDrbg.GetInternal()
        );
    }
}
 
 
 
 
 
bool cCryptoKey::IsValid(void) const
{
    return (mbedtls_pk_get_type(&m_Pk) != MBEDTLS_PK_NONE);
}