No need for stringification. It's all numbers (or bits). MD5, for example, processes 512 bits of input at a time. That's 8 64 bit integers or 16 32 bit integers (or 128 8 bit characters). Just concatenate your numbers to get 512 bit chunks of input.

If you go with CRC, then use a polynomial for the number of bits per integer you want to use: CRC-32 takes 32 bit integers as input. CRC-64 takes 64 bit integers.

I don't know what level of integrity checking you need, but you said "signature". So maybe you should consider one of the SHA-2 algorithms. as I interpret the descriptions, the 256 variant takes 512 bit inputs while the 512 variant takes 1024 bit inputs.