Bitcoind & others uses hex public keys, others use base58. javacript conversion at:
Bitcoind & others use WIF private keys, Digital Bazaar javacript uses something else. WIF for testnet private keys is slightly different then mainnet, and many existing tools only support mainnet WIF.
Based on a private key, there can be multiple public keys. We only use the compressed positive one. There is a tool for that (and does the WIF conversation) but it doesn’t work with testnet keys:
– Christopher Allen