We are currently working on deploying a Java Card applet onto the eSIM (eUICC) inside an iPhone. According to the GSMA SGP specifications, the eUICC is expected to support Java Card 3.0.5 Classic Edition. As defined in the Java Card 3.0.5 specification, the javacardx.crypto package should support standard algorithms including MessageDigest.ALG_HMAC_SHA_512. However, during our testing on the iPhone's embedded eSIM, we found that ALG_HMAC_SHA_512 appears to be unsupported or disabled. The same applet functions correctly on external Java Card platforms that support Java Card 3.0.5, leading us to believe that this is a restriction specific to the iPhone’s eUICC implementation. Our main questions are: Why is ALG_HMAC_SHA_512, which is part of the standard Java Card 3.0.5 specification, not available on the iPhone eSIM? Has Apple imposed any internal restrictions or exclusions on certain crypto algorithms for security, performance, or compliance reasons? Is there a list or documentation of supported and unsupported Java Card APIs or algorithms on the eUICC used in iPhones? Any insights from Apple engineers or other developers with experience on this topic would be greatly appreciated. Thank you in advance!